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Sample records for induction motor rotor

  1. Equivalence Between Squirrel Cage and Sheet Rotor Induction Motor

    NASA Astrophysics Data System (ADS)

    Dwivedi, Ankita; Singh, S. K.; Srivastava, R. K.

    2016-06-01

    Due to topological changes in dual stator induction motor and high cost of its fabrication, it is convenient to replace the squirrel cage rotor with a composite sheet rotor. For an experimental machine, the inner and outer stator stampings are normally available whereas the procurement of rotor stampings is quite cumbersome and is not always cost effective. In this paper, the equivalence between sheet/solid rotor induction motor and squirrel cage induction motor has been investigated using layer theory of electrical machines, so as to enable one to utilize sheet/solid rotor in dual port experimental machines.

  2. Fuzzy Logic Based Rotor Health Index of Induction Motor

    NASA Astrophysics Data System (ADS)

    Misra, Rajul; Pahuja, G. L.

    2015-10-01

    This paper presents an experimental study on detection and diagnosis of broken rotor bars in Squirrel Cage Induction Motor (SQIM). The proposed scheme is based on Motor Current Signature Analysis (MCSA) which uses amplitude difference of supply frequency to upper and lower side bands. Initially traditional MCSA has been used for rotor fault detection. It provides rotor health index on full load conditions. However in real practice if a fault occurs motor can not run at full load. To overcome the issue of reduced load condition a Fuzzy Logic based MCSA has been designed, implemented, tested and compared with traditional MCSA. A simulation result shows that proposed scheme is not only capable of detecting the severity of rotor fault but also provides remarkable performance at reduced load conditions.

  3. Broken-Rotor-Bar Diagnosis for Induction Motors

    NASA Astrophysics Data System (ADS)

    Wang, Jinjiang; Gao, Robert X.; Yan, Ruqiang

    2011-07-01

    Broken rotor bar is one of the commonly encountered induction motor faults that may cause serious motor damage to the motor if not detected timely. Past efforts on broken rotor bar diagnosis have been focused on current signature analysis using spectral analysis and wavelet transform. These methods require accurate slip estimation to localize fault-related frequency. This paper presents a new approach to broken rotor bar diagnosis without slip estimation, based on the ensemble empirical mode decomposition (EEMD) and the Hilbert transform. Specifically, the Hilbert transform first extracts the envelope of the motor current signal, which contains broken rotor fault-related frequency information. Subsequently, the envelope signal is adaptively decomposed into a number of intrinsic mode functions (IMFs) by the EEMD algorithm. Two criteria based on the energy and correlation analyses have been investigated to automate the IMF selection. Numerical and experimental studies have confirmed that the proposed approach is effective in diagnosing broken rotor bar faults for improved induction motor condition monitoring and damage assessment.

  4. Offline detection of broken rotor bars in AC induction motors

    NASA Astrophysics Data System (ADS)

    Powers, Craig Stephen

    ABSTRACT. OFFLINE DETECTION OF BROKEN ROTOR BARS IN AC INDUCTION MOTORS. The detection of the broken rotor bar defect in medium- and large-sized AC induction machines is currently one of the most difficult tasks for the motor condition and monitoring industry. If a broken rotor bar defect goes undetected, it can cause a catastrophic failure of an expensive machine. If a broken rotor bar defect is falsely determined, it wastes time and money to physically tear down and inspect the machine only to find an incorrect diagnosis. Previous work in 2009 at Baker/SKF-USA in collaboration with the Korea University has developed a prototype instrument that has been highly successful in correctly detecting the broken rotor bar defect in ACIMs where other methods have failed. Dr. Sang Bin and his students at the Korea University have been using this prototype instrument to help the industry save money in the successful detection of the BRB defect. A review of the current state of motor conditioning and monitoring technology for detecting the broken rotor bar defect in ACIMs shows improved detection of this fault is still relevant. An analysis of previous work in the creation of this prototype instrument leads into the refactoring of the software and hardware into something more deployable, cost effective and commercially viable.

  5. Novel indices for broken rotor bars fault diagnosis in induction motors using wavelet transform

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Bashir Mahdi; Faiz, Jawad; Lotfi-fard, S.; Pillay, P.

    2012-07-01

    This paper introduces novel indices for broken rotor bars diagnosis in three-phase induction motors based on wavelet coefficients of stator current in a specific frequency band. These indices enable to diagnose occurrence and determine number of broken bars in different loads precisely. Besides thanks to the suitability of wavelet transform in transient conditions, it is possible to detect the fault during the start-up of the motor. This is important in the case of start-up of large induction motors with long starting time and also motors with frequent start-up. Furthermore, broken rotor bars in induction motor are detected using spectra analysis of the stator current. It is also shown that rise of number of broken bars and load levels increases amplitude of the particular side-band components of the stator currents in the faulty case. An induction motor with 1, 2, 3 and 4 broken bars at the rated load and the motor with 4 broken bars at no-load, 33%, 66%, 100% and 133% rated load are investigated. Time stepping finite element method is used for modeling broken rotor bars faults in induction motors. In this modeling, effects of the stator winding distribution, stator and rotor slots, geometrical and physical characteristics of different parts of the motor and non-linearity of the core materials are taken into account. The simulation results are are verified by the experimental results.

  6. A Comparison of Different Techniques for Induction Motor Rotor Fault Diagnosis

    NASA Astrophysics Data System (ADS)

    Alwodai, A.; Gu, F.; Ball, A. D.

    2012-05-01

    The problem of failures in induction motors is a large concern due to its significant influence over industrial production. Therefore a large number of detection techniques were presented to avoid this problem. This paper presents the comparison results of induction motor rotor fault detection using three methods: motor current signature analysis (MCSA), surface vibration (SV), and instantaneous angular speed (IAS). These three measurements were performed under different loads with three rotor conditions: baseline, one rotor bar broken and two rotor bar broken. The faults can be detected and diagnosed based on the amplitude difference of the characteristic frequency components of power spectrum. However IAS may be the best technique because it gives the clearest spectrum representation in which the largest amplitude change is observed due to the faults.

  7. Detection of broken rotor bar faults in induction motor at low load using neural network.

    PubMed

    Bessam, B; Menacer, A; Boumehraz, M; Cherif, H

    2016-09-01

    The knowledge of the broken rotor bars characteristic frequencies and amplitudes has a great importance for all related diagnostic methods. The monitoring of motor faults requires a high resolution spectrum to separate different frequency components. The Discrete Fourier Transform (DFT) has been widely used to achieve these requirements. However, at low slip this technique cannot give good results. As a solution for these problems, this paper proposes an efficient technique based on a neural network approach and Hilbert transform (HT) for broken rotor bar diagnosis in induction machines at low load. The Hilbert transform is used to extract the stator current envelope (SCE). Two features are selected from the (SCE) spectrum (the amplitude and frequency of the harmonic). These features will be used as input for neural network. The results obtained are astonishing and it is capable to detect the correct number of broken rotor bars under different load conditions.

  8. Emotional Learning Based Intelligent Controllers for Rotor Flux Oriented Control of Induction Motor

    NASA Astrophysics Data System (ADS)

    Abdollahi, Rohollah; Farhangi, Reza; Yarahmadi, Ali

    2014-08-01

    This paper presents design and evaluation of a novel approach based on emotional learning to improve the speed control system of rotor flux oriented control of induction motor. The controller includes a neuro-fuzzy system with speed error and its derivative as inputs. A fuzzy critic evaluates the present situation, and provides the emotional signal (stress). The controller modifies its characteristics so that the critics stress is reduced. The comparative simulation results show that the proposed controller is more robust and hence found to be a suitable replacement of the conventional PI controller for the high performance industrial drive applications.

  9. The Design and its Verification of the Double Rotor Double Cage Induction Motor

    NASA Astrophysics Data System (ADS)

    Sinha, Sumita; Deb, Nirmal K.; Biswas, Sujit K.

    2017-02-01

    The concept of a double rotor motor presented earlier and its equivalent circuit has been developed, showing a non-linear parameter content. The two rotors (which are recommended to be double cage type for development of high starting torque) can run with equal or unequal speed independently, depending on their individual loading. This paper presents the elaborate design procedure, step-by-step, for the double rotor double cage motor and verifies the designed data with that obtained from three separate tests (compared to two for conventional motor) on a prototype, such that optimum performance can be obtained from the motor.

  10. Sensorless FOC Performance Improved with On-Line Speed and Rotor Resistance Estimator Based on an Artificial Neural Network for an Induction Motor Drive.

    PubMed

    Gutierrez-Villalobos, Jose M; Rodriguez-Resendiz, Juvenal; Rivas-Araiza, Edgar A; Martínez-Hernández, Moisés A

    2015-06-29

    Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor.

  11. Sensorless FOC Performance Improved with On-Line Speed and Rotor Resistance Estimator Based on an Artificial Neural Network for an Induction Motor Drive

    PubMed Central

    Gutierrez-Villalobos, Jose M.; Rodriguez-Resendiz, Juvenal; Rivas-Araiza, Edgar A.; Martínez-Hernández, Moisés A.

    2015-01-01

    Three-phase induction motor drive requires high accuracy in high performance processes in industrial applications. Field oriented control, which is one of the most employed control schemes for induction motors, bases its function on the electrical parameter estimation coming from the motor. These parameters make an electrical machine driver work improperly, since these electrical parameter values change at low speeds, temperature changes, and especially with load and duty changes. The focus of this paper is the real-time and on-line electrical parameters with a CMAC-ADALINE block added in the standard FOC scheme to improve the IM driver performance and endure the driver and the induction motor lifetime. Two kinds of neural network structures are used; one to estimate rotor speed and the other one to estimate rotor resistance of an induction motor. PMID:26131677

  12. Homopolar motor with dual rotors

    DOEpatents

    Hsu, J.S.

    1998-12-01

    A homopolar motor has a field rotor mounted on a frame for rotation in a first rotational direction and for producing an electromagnetic field, and an armature rotor mounted for rotation on said frame within said electromagnetic field and in a second rotational direction counter to said first rotational direction of said field rotor. The two rotors are coupled through a 1:1 gearing mechanism, so as to travel at the same speed but in opposite directions. This doubles the output voltage and output power, as compared to a motor in which only the armature is rotated. Several embodiments are disclosed. 7 figs.

  13. Homopolar motor with dual rotors

    DOEpatents

    Hsu, John S.

    1998-01-01

    A homopolar motor (10) has a field rotor (15) mounted on a frame (11) for rotation in a first rotational direction and for producing an electromagnetic field, and an armature rotor (17) mounted for rotation on said frame (11) within said electromagnetic field and in a second rotational direction counter to said first rotational direction of said field rotor (15). The two rotors (15, 17) are coupled through a 1:1 gearing mechanism (19), so as to travel at the same speed but in opposite directions. This doubles the output voltage and output power, as compared to a motor in which only the armature is rotated. Several embodiments are disclosed.

  14. Detection of air-gap eccentricity and broken-rotor bar conditions in a squirrel-cage induction motor using the radial flux sensor

    SciTech Connect

    Hwang, Don-Ha; Woo, Byung-Chul; Sun, Jong-Ho; Kang, Dong-Sik; Han, Sang-Bo; Kim, Byung-Kuk; Cho, Youn-Hyun

    2008-04-01

    A new method for detecting eccentricity and broken rotor bar conditions in a squirrel-cage induction motor is proposed. Air-gap flux variation analysis is done using search coils, which are inserted at stator slots. Using this method, the leakage flux in radial direction can be directly detected. Using finite element method, the air-gap flux variation is accurately modeled and analyzed. From the results of the simulation, a motor under normal condition shows maximum magnetic flux density of 1.3 T. On the other hand, the eccentric air-gap condition displays about 1.1 T at 60 deg. and 1.6 T at 240 deg. A difference of flux density is 0.5 T in the abnormal condition, whereas no difference is detected in the normal motor. In the broken rotor bar conditions, the flux densities at 65 deg. and 155 deg. are about 0.4 T and 0.8 T, respectively. These simulation results are coincided with those of experiment. Consequently, the measurement of the magnetic flux at air gap is one of effective ways to discriminate the faulted conditions of the eccentricity and broken rotor bars.

  15. Cage-rotor induction motor inter-turn short circuit fault detection with and without saturation effect by MEC model.

    PubMed

    Naderi, Peyman

    2016-09-01

    The inter-turn short fault for the Cage-Rotor-Induction-Machine (CRIM) is studied in this paper and its local saturation is taken into account. However, in order to observe the exact behavior of machine, the Magnetic-Equivalent-Circuit (MEC) and nonlinear B-H curve are proposed to provide an insight into the machine model and saturation effect respectively. The electrical machines are generally operated near to their saturation zone due to some design necessities. Hence, when the machine is exposed to a fault such as short circuit or eccentricities, it is operated within its saturation zone and thus, time and space harmonics are integrated and as a result, current and torque harmonics are generated which the phenomenon cannot be explored when saturation is dismissed. Nonetheless, inter-turn short circuit may lead to local saturation and this occurrence is studied in this paper using MEC model. In order to achieve the mentioned objectives, two and also four-pole machines are modeled as two samples and the machines performances are analyzed in healthy and faulty cases with and without saturation effect. A novel strategy is proposed to precisely detect inter-turn short circuit fault according to the stator׳s lines current signatures and the accuracy of the proposed method is verified by experimental results.

  16. Static air-gap eccentricity fault diagnosis using rotor slot harmonics in line neutral voltage of three-phase squirrel cage induction motor

    NASA Astrophysics Data System (ADS)

    Oumaamar, Mohamed El Kamel; Maouche, Yassine; Boucherma, Mohamed; Khezzar, Abdelmalek

    2017-02-01

    The mixed eccentricity fault detection in a squirrel cage induction motor has been thoroughly investigated. However, a few papers have been related to pure static eccentricity fault and the authors focused on the RSH harmonics presented in stator current. The main objective of this paper is to present an alternative method based on the analysis of line neutral voltage taking place between the supply and the stator neutrals in order to detect air-gap static eccentricity, and to highlight the classification of all RSH harmonics in line neutral voltage. The model of squirrel cage induction machine relies on the rotor geometry and winding layout. Such developed model is used to analyze the impact of the pure static air-gap eccentricity by predicting the related frequencies in the line neutral voltage spectrum. The results show that the line neutral voltage spectrum are more sensitive to the air-gap static eccentricity fault compared to stator current one. The theoretical analysis and simulated results are confirmed by experiments.

  17. Comparison of capabilities of reluctance synchronous motor and induction motor

    NASA Astrophysics Data System (ADS)

    Štumberger, Gorazd; Hadžiselimović, Miralem; Štumberger, Bojan; Miljavec, Damijan; Dolinar, Drago; Zagradišnik, Ivan

    2006-09-01

    This paper compares the capabilities of a reluctance synchronous motor (RSM) with those of an induction motor (IM). An RSM and IM were designed and made, with the same rated power and speed. They differ only in the rotor portion while their stators, housings and cooling systems are identical. The capabilities of both motors in a variable speed drive are evaluated by comparison of the results obtained by magnetically nonlinear models and by measurements.

  18. Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature

    DOEpatents

    Kelledes, William L.; St. John, Don K.

    1992-01-01

    The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.

  19. Induction motor control

    NASA Astrophysics Data System (ADS)

    Hansen, Irving G.

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  20. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly utilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilizes induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  1. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  2. Prospects for Brushless ac Motors with HTS Rotors

    NASA Astrophysics Data System (ADS)

    McCulloch, M. D.; Jim, K.; Kawai, Y.; Dew-Hughes, D.; Morgan, C.; Goringe, M. J.; Grovenor, C. R. M.

    1997-03-01

    There is a superconducting equivalent for every type of brushless ac motor; permanent magnet, reluctance, hysteresis and induction (squirrel cage) motor. The particular advantage of superconducting versions of these machines is that they are expected to provide much higher power densities than their conventional equivalents. The behaviour of superconducting rotors fabricated in the form of (a) squirrell cages from silver coated with melt-processed Bi-2212, (b) tubes cast centifugally from Bi-2212, and (c) small cylinders of melt-processed and seeded YBCO has been studied in rotating magnetic fields provided by conventional motor coils. Measurements of static torque, and values of dynamic torque deduced from angular velocity and acceleration have been used to characterise the potential performance of these embryonic machines. Two broad types of behaviour have been observed. In the Bi-2212 rotors the torque decreases with increasing rotor speed; this behaviour is believed due to flux creep. By contrast the strong-pinning YBCO rotors maintain a constant torque up to synchronous speed. Mathematical modelling of flux penetration and distribution within the rotors is able to reproduce both types of the observed behaviour. Power densities some 5 to 10 times that of conventional machines are predicted to be achievable in optimised prototype machines.

  3. Electromechanical interaction in rotordynamics of cage induction motors

    NASA Astrophysics Data System (ADS)

    Holopainen, Timo P.; Tenhunen, Asmo; Arkkio, Antero

    2005-06-01

    Eccentric rotor motion induces an unbalanced magnetic pull between the rotor and stator of cage induction motors. Recently, a linear parametric model of this eccentricity force due to the arbitrary rotor motion was presented. The purpose of this study is to combine this electromagnetic force model with a simple mechanical rotor model, and further, to demonstrate the rotordynamic response induced by this electromechanical interaction. An electromechanical rotor model is derived on the basis of the Jeffcott rotor with two additional variables for the harmonic currents of the rotor cage. Applying this model, the rotordynamic effects of electromechanical interaction were studied. Three induction motors were used in the numerical examples. The electromechanical parameters of these motors were estimated from the numerical simulations carried out separately. The results obtained show that the electromechanical interaction may decrease the natural frequencies of the rotor, induce additional damping or cause rotordynamic instability. These interaction effects are most significant in motors operating at or near the first bending critical speed. Excluding the potential rotordynamic instability, the numerical results indicate that the electromechanical interaction reduces effectively the unbalance response close to the first bending critical speed.

  4. Initial Rotor Position Estimation of Half-Wave Rectified Brushless Synchronous Motor

    NASA Astrophysics Data System (ADS)

    Abe, Takashi; Oyama, Jun; Higuchi, Tsuyoshi

    This paper presents an initial rotor position estimation of Half-Wave Rectified Brushless Synchronous Motor. In the previous paper, we proposed this motor as AC servo motor, which is based on the half-wave rectified brushless excitation principle. The basic principle of this estimation technique utilizes the dependence of inductance on the rotor position. The bias frequency component of half-Wave rectified brushless excitation is used to estimate the rotor position error. The magnetic pole is discriminated by the switching condition of the diode inserted into the rotor field winding. This estimation technique is confirmed by simulation include inverter circuit, control program and motor model. Finally, the effectiveness of the proposed estimation technique has been verified by experiments.

  5. Dovetail Rotor Construction For Permanent-Magnet Motors

    NASA Technical Reports Server (NTRS)

    Kintz, Lawrence J., Jr.; Puskas, William J.

    1988-01-01

    New way of mounting magnets in permanent-magnet, electronically commutated, brushless dc motors. Magnets wedge shaped, tapering toward center of rotor. Oppositely tapered pole pieces, electron-beam welded to rotor hub, retain magnets against centrifugal force generated by spinning rotor. To avoid excessively long electron-beam welds, pole pieces assembled in segments rather than single long bars.

  6. Phase and speed synchronization control of four eccentric rotors driven by induction motors in a linear vibratory feeder with unknown time-varying load torques using adaptive sliding mode control algorithm

    NASA Astrophysics Data System (ADS)

    Kong, Xiangxi; Zhang, Xueliang; Chen, Xiaozhe; Wen, Bangchun; Wang, Bo

    2016-05-01

    In this paper, phase and speed synchronization control of four eccentric rotors (ERs) driven by induction motors in a linear vibratory feeder with unknown time-varying load torques is studied. Firstly, the electromechanical coupling model of the linear vibratory feeder is established by associating induction motor's model with the dynamic model of the system, which is a typical under actuated model. According to the characteristics of the linear vibratory feeder, the complex control problem of the under actuated electromechanical coupling model converts to phase and speed synchronization control of four ERs. In order to keep the four ERs operating synchronously with zero phase differences, phase and speed synchronization controllers are designed by employing adaptive sliding mode control (ASMC) algorithm via a modified master-slave structure. The stability of the controllers is proved by Lyapunov stability theorem. The proposed controllers are verified by simulation via Matlab/Simulink program and compared with the conventional sliding mode control (SMC) algorithm. The results show the proposed controllers can reject the time-varying load torques effectively and four ERs can operate synchronously with zero phase differences. Moreover, the control performance is better than the conventional SMC algorithm and the chattering phenomenon is attenuated. Furthermore, the effects of reference speed and parametric perturbations are discussed to show the strong robustness of the proposed controllers. Finally, experiments on a simple vibratory test bench are operated by using the proposed controllers and without control, respectively, to validate the effectiveness of the proposed controllers further.

  7. Rotor fault condition monitoring techniques for squirrel-cage induction machine—A review

    NASA Astrophysics Data System (ADS)

    Mehrjou, Mohammad Rezazadeh; Mariun, Norman; Hamiruce Marhaban, Mohammad; Misron, Norhisam

    2011-11-01

    Nowadays, manufacturing companies are making great efforts to implement an effective machinery maintenance program, which provides incipient fault detection. The machine problem and its irregularity can be detected at an early stage by employing a suitable condition monitoring accompanied with powerful signal processing technique. Among various defects occurred in machines, rotor faults are of significant importance as they cause secondary failures that lead to a serious motor malfunction. Diagnosis of rotor failures has long been an important but complicated task in the area of motor faults detection. This paper intends to review and summarize the recent researches and developments performed in condition monitoring of the induction machine with the purpose of rotor faults detection. The aim of this article is to provide a broad outlook on rotor fault monitoring techniques for the researchers and engineers.

  8. Demonstration of Lenz's Law with an Induction Motor

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2005-01-01

    The interaction of a conductor with a time-dependent magnetic field is an important topic of electromagnetic theory. A computerized classroom demonstration shows how the eddy currents induced in the rotor of an induction motor cause its rotation or braking. Both phenomena are directly related to Lenz's law.

  9. Disc rotors with permanent magnets for brushless DC motor

    DOEpatents

    Hawsey, Robert A.; Bailey, J. Milton

    1992-01-01

    A brushless dc permanent magnet motor drives an autonomous underwater vehe. In one embodiment, the motor comprises four substantially flat stators in stacked relationship, with pairs of the stators axially spaced, each of the stators comprising a tape-wound stator coil, and first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of permanent magnets embedded therein. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and a drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs of rotors mounted on opposite sides of the stators and driven by counterrotating shafts.

  10. Synchronous motor with hybrid permanent magnets on the rotor.

    PubMed

    Slusarek, Barbara; Kapelski, Dariusz; Antal, Ludwik; Zalas, Pawel; Gwoździewicz, Maciej

    2014-07-10

    Powder metallurgy allows designers of electric motors to implement new magnetic circuit structures. A relatively new concept is the use of a magnet system consisting of various types of magnets on one rotor, for example sintered and bonded magnets. This concept has been applied to the design and manufacture of the four-pole rotor of a synchronous motor with 400 W power and a rotational speed of 1500 rpm. In this motor, the stator of an asynchronous motor type Sh 71-4B is applied. The application of the new construction of the rotor resulted in an increase in motor efficiency and power factor compared to an asynchronous motor with the same volume.

  11. Segmented rail linear induction motor

    DOEpatents

    Cowan, Jr., Maynard; Marder, Barry M.

    1996-01-01

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.

  12. Segmented rail linear induction motor

    DOEpatents

    Cowan, M. Jr.; Marder, B.M.

    1996-09-03

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.

  13. Position Sensing for Rotor in Hybrid Stepper Motor

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor); Alhorn, Dean C. (Inventor); Smith, Dennis A. (Inventor)

    2011-01-01

    A method and system are provided for sensing the position of a rotor in a hybrid stepper motor. First and second Hall sensors are positioned in a spaced-apart relationship with the first and second armatures of the rotor such that the first and second Hall sensors generate electrical outputs that are 90.degree. out of phase with one another as the rotor rotates. The electrical outputs are adjusted relative to a reference, and the amplitude of the electrical outputs is further adjusted to account for spacing differences between the rotor and each of the first and second Hall sensors.

  14. Forward and reverse control system for induction motors

    DOEpatents

    Wright, J.T.

    1987-09-15

    A control system for controlling the direction of rotation of a rotor of an induction motor includes an array of five triacs with one of the triacs applying a current of fixed phase to the windings of the rotor and four of the triacs being switchable to apply either hot ac current or return ac current to the stator windings so as to reverse the phase of current in the stator relative to that of the rotor and thereby reverse the direction of rotation of the rotor. Switching current phase in the stator is accomplished by operating the gates of pairs of the triacs so as to connect either hot ac current or return ac current to the input winding of the stator. 1 fig.

  15. Sensorless Modeling of Varying Pulse Width Modulator Resolutions in Three-Phase Induction Motors

    PubMed Central

    Marko, Matthew David; Shevach, Glenn

    2017-01-01

    A sensorless algorithm was developed to predict rotor speeds in an electric three-phase induction motor. This sensorless model requires a measurement of the stator currents and voltages, and the rotor speed is predicted accurately without any mechanical measurement of the rotor speed. A model of an electric vehicle undergoing acceleration was built, and the sensorless prediction of the simulation rotor speed was determined to be robust even in the presence of fluctuating motor parameters and significant sensor errors. Studies were conducted for varying pulse width modulator resolutions, and the sensorless model was accurate for all resolutions of sinusoidal voltage functions. PMID:28076418

  16. Sensorless Modeling of Varying Pulse Width Modulator Resolutions in Three-Phase Induction Motors.

    PubMed

    Marko, Matthew David; Shevach, Glenn

    2017-01-01

    A sensorless algorithm was developed to predict rotor speeds in an electric three-phase induction motor. This sensorless model requires a measurement of the stator currents and voltages, and the rotor speed is predicted accurately without any mechanical measurement of the rotor speed. A model of an electric vehicle undergoing acceleration was built, and the sensorless prediction of the simulation rotor speed was determined to be robust even in the presence of fluctuating motor parameters and significant sensor errors. Studies were conducted for varying pulse width modulator resolutions, and the sensorless model was accurate for all resolutions of sinusoidal voltage functions.

  17. Theoretical analysis of a YBCO squirrel-cage type induction motor based on an equivalent circuit

    NASA Astrophysics Data System (ADS)

    Morita, G.; Nakamura, T.; Muta, I.

    2006-06-01

    A HTS induction motor, with a HTS squirrel-cage rotor, is analysed using an electrical equivalent circuit. The squirrel-cage winding in the rotor consists of rotor bars and end rings, and both are considered to be made of YBCO film conductors. A wide range of electric field versus current density in YBCO film is formulated based on the Weibull function, and analysed as a non-linear resistance in the equivalent circuit. It is shown that starting and accelerating torques of the HTS induction motor are improved drastically compared to those of a conventional induction motor. Furthermore, large synchronous torque can also be realized by trapping the magnetic flux in the rotor circuit because of the persistent current mode.

  18. Online Monitoring of Induction Motors

    SciTech Connect

    McJunkin, Timothy R.; Agarwal, Vivek; Lybeck, Nancy Jean

    2016-01-01

    The online monitoring of active components project, under the Advanced Instrumentation, Information, and Control Technologies Pathway of the Light Water Reactor Sustainability Program, researched diagnostic and prognostic models for alternating current induction motors (IM). Idaho National Laboratory (INL) worked with the Electric Power Research Institute (EPRI) to augment and revise the fault signatures previously implemented in the Asset Fault Signature Database of EPRI’s Fleet Wide Prognostic and Health Management (FW PHM) Suite software. Induction Motor diagnostic models were researched using the experimental data collected by Idaho State University. Prognostic models were explored in the set of literature and through a limited experiment with 40HP to seek the Remaining Useful Life Database of the FW PHM Suite.

  19. Induction machine

    DOEpatents

    Owen, Whitney H.

    1980-01-01

    A polyphase rotary induction machine for use as a motor or generator utilizing a single rotor assembly having two series connected sets of rotor windings, a first stator winding disposed around the first rotor winding and means for controlling the current induced in one set of the rotor windings compared to the current induced in the other set of the rotor windings. The rotor windings may be wound rotor windings or squirrel cage windings.

  20. Rotation of artificial rotor axles in rotary molecular motors.

    PubMed

    Baba, Mihori; Iwamoto, Kousuke; Iino, Ryota; Ueno, Hiroshi; Hara, Mayu; Nakanishi, Atsuko; Kishikawa, Jun-Ichi; Noji, Hiroyuki; Yokoyama, Ken

    2016-10-04

    F1- and V1-ATPase are rotary molecular motors that convert chemical energy released upon ATP hydrolysis into torque to rotate a central rotor axle against the surrounding catalytic stator cylinder with high efficiency. How conformational change occurring in the stator is coupled to the rotary motion of the axle is the key unknown in the mechanism of rotary motors. Here, we generated chimeric motor proteins by inserting an exogenous rod protein, FliJ, into the stator ring of F1 or of V1 and tested the rotation properties of these chimeric motors. Both motors showed unidirectional and continuous rotation, despite no obvious homology in amino acid sequence between FliJ and the intrinsic rotor subunit of F1 or V1 These results showed that any residue-specific interactions between the stator and rotor are not a prerequisite for unidirectional rotation of both F1 and V1 The torque of chimeric motors estimated from viscous friction of the rotation probe against medium revealed that whereas the F1-FliJ chimera generates only 10% of WT F1, the V1-FliJ chimera generates torque comparable to that of V1 with the native axle protein that is structurally more similar to FliJ than the native rotor of F1 This suggests that the gross structural mismatch hinders smooth rotation of FliJ accompanied with the stator ring of F1.

  1. Rotation of artificial rotor axles in rotary molecular motors

    PubMed Central

    Baba, Mihori; Iwamoto, Kousuke; Ueno, Hiroshi; Hara, Mayu; Nakanishi, Atsuko; Kishikawa, Jun-ichi; Noji, Hiroyuki; Yokoyama, Ken

    2016-01-01

    F1- and V1-ATPase are rotary molecular motors that convert chemical energy released upon ATP hydrolysis into torque to rotate a central rotor axle against the surrounding catalytic stator cylinder with high efficiency. How conformational change occurring in the stator is coupled to the rotary motion of the axle is the key unknown in the mechanism of rotary motors. Here, we generated chimeric motor proteins by inserting an exogenous rod protein, FliJ, into the stator ring of F1 or of V1 and tested the rotation properties of these chimeric motors. Both motors showed unidirectional and continuous rotation, despite no obvious homology in amino acid sequence between FliJ and the intrinsic rotor subunit of F1 or V1. These results showed that any residue-specific interactions between the stator and rotor are not a prerequisite for unidirectional rotation of both F1 and V1. The torque of chimeric motors estimated from viscous friction of the rotation probe against medium revealed that whereas the F1-FliJ chimera generates only 10% of WT F1, the V1-FliJ chimera generates torque comparable to that of V1 with the native axle protein that is structurally more similar to FliJ than the native rotor of F1. This suggests that the gross structural mismatch hinders smooth rotation of FliJ accompanied with the stator ring of F1. PMID:27647891

  2. Temperature analysis of induction motors using a hybrid thermal model with distributed heat sources

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S. C.; Pal, S. K.

    1998-06-01

    The article presents a hybrid thermal model for the accurate estimation of temperature distribution of induction motors. The developed model is a combination of lumped and distributed thermal parameters which are obtained from motor dimensions and other constants such as material density, specific heats, thermal conductivity, etc. The model is especially suited for the derating of induction motors operating under distorted and unbalanced supply condition. The model have been applied to a small (2hp, 415 V, 3-phase) cage rotor induction motor. The performance of the model is confirmed by experimental temperature data from the body and the conductor inside the slots of the motor.

  3. Electromechanical Interaction in Eccentric-Rotor Cage Induction Machine Equipped with a Self-Bearing Force Actuator

    NASA Astrophysics Data System (ADS)

    Laiho, Antti; Tammi, Kari; Orivuori, Juha; Sinervo, Anssi; Zenger, Kai; Arkkio, Antero

    In this paper, flexural rotor vibration in a two-pole cage induction machine equipped with a built-in force actuator is examined. The built-in force actuator is based on the self-bearing machine technology in which a supplementary winding is placed in the machine for force production. The built-in force actuator enables active vibration control, but also it enables excitation of the machine for purposes of condition monitoring, for instance. A low-order parametric model is derived for the actuator-rotor system. In the model, the arbitrary eccentric rotor motion is coupled with the voltage-flux equations for the supplementary winding and eccentric rotor cage. Furthermore, based on frequency-domain system identification, a control method is examined for compensating synchronous rotor vibration. Experimental results are given for a two-pole cage induction motor. The main contribution of the article is to couple eccentric rotor motion, the built-in force actuator and the mechanical rotor model to obtain a low-order parametric model of the actuator-rotor system which can be applied to control design for rotor vibration suppression.

  4. Analytical calculation of the RFOC method in single-phase induction motor

    NASA Astrophysics Data System (ADS)

    Jannati, M.; Monadi, A.; Idris, N. R. N.; Faudzi, A. A. M.

    2016-05-01

    This study discusses the different techniques for speed control of single-phase induction motor with two asymmetrical main and auxiliary windings based on Rotor Field-Oriented Control (RFOC) method. In the presented methods, transformation matrices are introduced and applied to the equations of single-phase induction motor. It is shown by applying these rotational transformations to the unbalanced equations of single-phase induction motor, equations of single-phase induction motor are transformed into symmetrical equations. These rotational transformations are achieved based from the steady-state equivalent circuit of single-phase induction motor. Finally, a method for RFOC of single-phase induction motor is proposed. Results show the good performance of the proposed method.

  5. Analytical and experimental study of high phase order induction motors

    NASA Technical Reports Server (NTRS)

    Klingshirn, Eugene A.

    1989-01-01

    Induction motors having more than three phases were investigated to determine their suitability for electric vehicle applications. The objective was to have a motor with a current rating lower than that of a three-phase motor. The name chosen for these is high phase order (HPO) motors. Motors having six phases and nine phases were given the most attention. It was found that HPO motors are quite suitable for electric vehicles, and for many other applications as well. They have characteristics which are as good as or better than three-phase motors for practically all applications where polyphase induction motors are appropriate. Some of the analysis methods are presented, and several of the equivalent circuits which facilitate the determination of harmonic currents and losses, or currents with unbalanced sources, are included. The sometimes large stator currents due to harmonics in the source voltages are pointed out. Filters which can limit these currents were developed. An analysis and description of these filters is included. Experimental results which confirm and illustrate much of the theory are also included. These include locked rotor test results and full-load performance with an open phase. Also shown are oscillograms which display the reduction in harmonic currents when a filter is used with the experimental motor supplied by a non-sinusoidal source.

  6. An electrical gearbox by means of pole variation for induction and superconducting disc motor

    NASA Astrophysics Data System (ADS)

    Inácio, S.; Inácio, D.; Pina, J. M.; Valtchev, S.; Neves, M. V.; Rodrigues, A. L.

    2008-02-01

    In this paper, a poly-phase disc motor innovative feeding and control strategy, based on a variable poles approach, and its application to a HTS disc motor, are presented. The stator windings may be electronically commutated to implement a 2, 4, 6 or 8 poles winding, thus changing the motor's torque/speed characteristics. The motor may be a conventional induction motor with a conductive disc rotor, or a new HTS disc motor, with conventional copper windings at its two iron semi-stators, and a HTS disc as a rotor. The conventional induction motor's operation principle is related with the induced electromotive forces in the conductive rotor. Its behaviour, characteristics (namely their torque/speed characteristics for different number of pole pairs) and modelling through Steinmetz and others theories are well known. The operation principle of the motor with HTS rotor, however, is rather different and is related with vortices' dynamics and pinning characteristics; this is a much more complex process than induction, and its modelling is quite complicated. In this paper, the operation was simulated through finite-elements commercial software, whereas superconductivity was simulated by the E-J power law. The Electromechanical performances of both motors where computed and are presented and compared. Considerations about the systems overall efficiency, including cryogenics, are also discussed.

  7. Unstable force analysis for induction motor eccentricity

    NASA Astrophysics Data System (ADS)

    Han, Xu; Palazzolo, Alan

    2016-05-01

    The increasing popularity of motors in machinery trains has led to an intensified interest in the forces they produce that may influence machinery vibration. Motor design typically assumes a uniform air gap, however in practice all motors operate with the rotor slightly displaced from the motor centerline in what is referred to as an eccentric position. Rotor center eccentricity can cause a radially unbalanced magnetic field when the motor is operating. This will results in both a radial force pulling the motor further away from the center, and a tangential force which can induce a vibration stability problem. In this paper, a magnetic equivalent circuit MEC modeling method is proposed to calculate both the radial and tangential motor eccentric force. The treatment of tangential force determination is rarely addressed, but it is very important for rotordynamic vibration stability evaluation. The proposed model is also coupled with the motor electric circuit model to provide capability for transient vibration simulations. FEM is used to verify the MEC model. A parametric study is performed on the motor radial and tangential eccentric forces. Also a Jeffcott rotor model is used to study the influence of the motor eccentric force on mechanical vibration stability and nonlinear behavior. Furthermore, a stability criteria for the bearing damping is provided. The motor radial and tangential eccentric forces are both curved fitted to include their nonlinearity in time domain transient simulation for both a Jeffcott rotor model and a geared machinery train with coupled torsional-lateral motion. Nonlinear motions are observed, including limit cycles and bifurcation induced vibration amplitude jumps.

  8. Method and system for determining induction motor speed

    DOEpatents

    Parlos, Alexander G.; Bharadwaj, Raj M.

    2004-03-30

    A non-linear, semi-parametric neural network-based adaptive filter is utilized to determine the dynamic speed of a rotating rotor within an induction motor, without the explicit use of a speed sensor, such as a tachometer, is disclosed. The neural network-based filter is developed using actual motor current measurements, voltage measurements, and nameplate information. The neural network-based adaptive filter is trained using an estimated speed calculator derived from the actual current and voltage measurements. The neural network-based adaptive filter uses voltage and current measurements to determine the instantaneous speed of a rotating rotor. The neural network-based adaptive filter also includes an on-line adaptation scheme that permits the filter to be readily adapted for new operating conditions during operations.

  9. Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency

    SciTech Connect

    John G. Cowie; Edwin F. Brush, Jr.; Dale T. Peters; Stephen P. Midson; Darryl J. Van Son

    2003-05-01

    The objective of the study, Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency, was to support the Copper Development Association (CDA) in its effort to design, fabricate and demonstrate mold technologies designed to withstand the copper motor rotor die casting environment for an economically acceptable life. The anticipated result from the compiled data and tests were to: (1) identify materials suitable for die casting copper, (2) fabricate motor rotor molds and (3) supply copper rotor motors for testing in actual compressor systems. Compressor manufacturers can apply the results to assess the technical and economical viability of copper rotor motors.

  10. Effect of skewing the rotor teeth on the performance of doubly salient permanent magnet motors

    NASA Astrophysics Data System (ADS)

    Sheth, N. K.; Sekharbabu, A. R. C.; Rajagopal, K. R.

    2006-04-01

    This paper presents the effects of skewing the rotor teeth on the performance characteristics such as flux linkage, back emf, phase inductance, and reluctance torque of an 8/6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the two-dimensional finite element analysis. The optimum skewing angle is obtained as 12°-15° for the least ripple torque without much reduction in the back emf. Skewing the rotor teeth of an 8/6 doubly salient permanent magnet motor by 12°-15° will reduce the total harmonic distortion of the back emf profile to 29.69% from the original value of 44.69%. The reduction in the amplitude of the back emf in this case will be 18.79% only.

  11. Rotor compound concept for designing an industrial HTS synchronous motor

    NASA Astrophysics Data System (ADS)

    Kashani, M.; Hosseina, M.; Sarrafan, K.; Darabi, A.

    2013-06-01

    Recently, producing power with smaller amount of losses become as a goal in our daily life. Today, large amount of energy waste in power networks all around the world. The main reason is “resistive electric equipments” of power networks. Since early 1980s, simultaneous with the development of high temperature superconductive (HTS) technology, superconductors gently attracted the mankind attentions. Using superconductive equipments instead of conventional resistive ones are result in salient electric loss reduction in power systems. Especially to reduce losses in power networks superconductive industrial rotating machines can potentially perform a significant role. In early recent century, first generation of HTS rotating machines was born. But unfortunately they have long way to penetrate the commercial markets yet. In HTS rotating machines the conventional copper made windings are replaced with the HTS superconductors. In this paper an industrial HTS synchronous motor with YBCO coated conductor field windings was designed. As a new approach, model was equipped with a compound rotor that includes both magnetic and non-magnetic materials. So, large amount of heavy iron made part was replaced by light non-magnetic material such as G-10 fiberglass. Furthermore, in this structure iron loss in rotor could be reduced to its lowest value. Also less weight and more air gap energy density were the additional advantages. Regarding zero electric loss production in field windings and less iron loss in rotor construction, this model potentially is more effective than the other iron made HTS motors.

  12. A validated model for the prediction of rotor bar failure in squirrel-cage motors using instantaneous angular speed

    NASA Astrophysics Data System (ADS)

    Sasi, Ahmed Y. Ben; Gu, Fengshou; Li, Yuhua; Ball, Andrew D.

    2006-10-01

    Instantaneous angular speed (IAS)-based condition monitoring is an area in which significant progress has been achieved over the recent years. This condition monitoring technique is less known compared to the existing conventional methods. This paper presents model-predicted simulation and experimental results of broken rotor bar faults in a three-phase induction motor using IAS variations. The simulation was performed under normal, and a broken rotor bar fault. The present paper evaluates through simulating and measuring the IAS of an induction motor at broken rotor bar faults in both time and frequency domains. Experimental results show a good agreement with the model-predicted simulation results. Three vital key features were extracted from the angular speed variations. One feature is the modulating contour of pole pass frequency periods in time domain. The other two features are in frequency domain. The primary feature is the presence of the pole pass frequency component at the low-frequency region of the IAS spectrum. The secondary feature which are the multiple of pole pass frequency sideband components around the rotor speed frequency component. Experimental results confirm the validity of the simulation results for the proposed method. The IAS has demonstrated more sensitivity than current signature analysis in detecting the fault. This research also shows the power of angular speed features as a useful tool to detect broken rotor bar deteriorations using any economical transducer such as low-resolution rotary shaft encoders; which may well be already installed for process control purposes.

  13. An Inverter-Driven Induction Motor System with a Deadlock Breaking Capability

    NASA Astrophysics Data System (ADS)

    Ichikawa, Takuto; Yoshida, Toshiya; Miyashita, Osamu

    Induction motors are very widely used in various industrial applications. In semiconductor manufacturing processes, deadlock failure of pumps may occur by the adhering of glass material contained in the gas to the rotor. This can lead to the shutdown of the manufacturing plant. Therefore, a countermeasure to prevent deadlocking of a motor is required. This paper proposes a method for generating an impulse torque in an induction motor fed by an inverter. The proposed inverter circuit is composed of a conventional inverter and a few additional relays. The on-and-off control of the relays supplies an appropriate magnetizing current and a large torque current from the dc-link capacitor. In experiment, a 1.5-kW cage-type induction motor generated a torque that was approximately seven times larger than the rated torque of the motor. This large impulse torque is useful for breaking the motor deadlock.

  14. Three-Dimensional Temperature Field Simulation for the Rotor of an Asynchronous Motor

    ERIC Educational Resources Information Center

    Wang, Yanwu; Fan, Chunli; Yang, Li; Sun, Fengrui

    2010-01-01

    A three-dimensional heat transfer model is built according to the rotor structure of an asynchronous motor, and three-dimensional temperature fields of the rotor under different working conditions, such as the unloaded, rated loaded and that with broken rotor bars, are studied based on the finite element numerical method and experiments. The…

  15. Stability synthesis of control system in current fed inverter driven induction motor

    SciTech Connect

    Veda, R.; Irisa, T.; Ito, T.; Mochizuki, T.; Sonoda, T.

    1983-01-01

    This paper presents a new method of synthesizing a stabilizing control system in current fed inverter driven induction motor (CFIDIM). The method is focused on rotor dynamics and a concept of ''damping torque coefficient (DTC)'' is introduced concerning the electrical torque. At first the control system is synthesized on the assumption that an induction motor is driven by an ideally controllable current source. Then perturbed linearized technique indicates that the system can be stabilized if the stator current or frequency is controlled so as to make the DTC positive by feeding back a signal composed of rotor speed. Next, based on this fact, an approach of synthesizing the converter output voltage is presented under a fixed stator frequency. This result clarifies that the stable operation can be achieved by controlling the voltage in proportion to the acceleration of rotor speed or the deviation of electrical torque. These analytical results are verified with laboratory field tests.

  16. Four quadrant control of induction motors

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1991-01-01

    Induction motors are the nation's workhorse, being the motor of choice in most applications due to their simple rugged construction. It has been estimated that 14 to 27 percent of the country's total electricity use could be saved with adjustable speed drives. Until now, induction motors have not been suited well for variable speed or servo-drives, due to the inherent complexity, size, and inefficiency of their variable speed controls. Work at NASA Lewis Research Center on field oriented control of induction motors using pulse population modulation method holds the promise for the desired drive electronics. The system allows for a variable voltage to frequency ratio which enables the user to operate the motor at maximum efficiency, while having independent control of both the speed and torque of an induction motor in all four quadrants of the speed torque map. Multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of machine. The pulse population technique, results to date, and projections for implementation of this existing new motor control technology are discussed.

  17. Advanced simulation model for IPM motor drive with considering phase voltage and stator inductance

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Myung; Park, Hyun-Jong; Lee, Ju

    2016-10-01

    This paper proposes an advanced simulation model of driving system for Interior Permanent Magnet (IPM) BrushLess Direct Current (BLDC) motors driven by 120-degree conduction method (two-phase conduction method, TPCM) that is widely used for sensorless control of BLDC motors. BLDC motors can be classified as SPM (Surface mounted Permanent Magnet) and IPM motors. Simulation model of driving system with SPM motors is simple due to the constant stator inductance regardless of the rotor position. Simulation models of SPM motor driving system have been proposed in many researches. On the other hand, simulation models for IPM driving system by graphic-based simulation tool such as Matlab/Simulink have not been proposed. Simulation study about driving system of IPMs with TPCM is complex because stator inductances of IPM vary with the rotor position, as permanent magnets are embedded in the rotor. To develop sensorless scheme or improve control performance, development of control algorithm through simulation study is essential, and the simulation model that accurately reflects the characteristic of IPM is required. Therefore, this paper presents the advanced simulation model of IPM driving system, which takes into account the unique characteristic of IPM due to the position-dependent inductances. The validity of the proposed simulation model is validated by comparison to experimental and simulation results using IPM with TPCM control scheme.

  18. Development of a cryogenic induction motor for use with a superconducting magnetic bearing

    NASA Astrophysics Data System (ADS)

    Matsumura, Tomotake; Hanany, Shaul; Hull, John R.; Johnson, Bradley; Jones, Terry; Oxley, Paul K.

    2005-10-01

    We have constructed a cryogenic induction motor to turn the rotor of a superconducting magnetic bearing (SMB). Both the motor and the SMB are operated at liquid He temperatures. We give a model for the motor and present measurements of its operation. The rotation speed is very stable. Over 8 h it shows an RMS variation of only 0.005 Hz from a mean of 2 Hz. The speed variation within one period of rotation is 3% ± 1% implying that the angular position of the rotor can be determined to an accuracy of 1° for all angles of rotation even if angular position is encoded only once every period. Friction and heat dissipation in this motor is dominated by eddy currents. We discuss the application of the motor to astrophysical polarimetry.

  19. Capacitance and Inductance based Rotor Ground Fault Location Method for Synchronous Machines

    NASA Astrophysics Data System (ADS)

    Palanisamy, Ramanathan

    2017-02-01

    This paper presents a capacitance and inductance based rotor ground fault location method for synchronous machines, which can detect and locate the ground fault in the rotor. The main contribution of this technique is to find the location of the ground fault in the rotor winding and reduce the repair time. This detection method is based on the measurement of inductance and capacitance of the rotor winding. It is suitable for salient pole synchronous machines. This method has been validated through experimental tests at the site.

  20. Control system for a wound-rotor motor

    DOEpatents

    Ellis, James N.

    1983-01-01

    A load switching circuit for switching two or more transformer taps under load carrying conditions includes first and second parallel connected bridge rectifier circuits which control the selective connection of a direct current load to taps of a transformer. The first bridge circuit is normally conducting so that the load is connected to a first tap through the first bridge circuit. To transfer the load to the second tap, a switch is operable to connect the second bridge circuit to a second tap, and when the second bridge circuit begins to conduct, the first bridge circuit ceases conduction because the potential at the second tap is higher than the potential at the first tap, and the load is thus connected to the second tap through the second bridge circuit. The load switching circuit is applicable in a motor speed controller for a wound-rotor motor for effecting tap switching as a function of motor speed while providing a stepless motor speed control characteristic.

  1. FORTRAN program for induction motor analysis

    NASA Technical Reports Server (NTRS)

    Bollenbacher, G.

    1976-01-01

    A FORTRAN program for induction motor analysis is described. The analysis includes calculations of torque-speed characteristics, efficiency, losses, magnetic flux densities, weights, and various electrical parameters. The program is limited to three-phase Y-connected, squirrel-cage motors. Detailed instructions for using the program are given. The analysis equations are documented, and the sources of the equations are referenced. The appendixes include a FORTRAN symbol list, a complete explanation of input requirements, and a list of error messages.

  2. INSPECTION MEANS FOR INDUCTION MOTORS

    DOEpatents

    Williams, A.W.

    1959-03-10

    an appartus is descripbe for inspcting electric motors and more expecially an appartus for detecting falty end rings inn suqirrel cage inductio motors while the motor is running. In its broua aspects, the mer would around ce of reference tedtor means also itons in the phase ition of the An electronic circuit for conversion of excess-3 binary coded serial decimal numbers to straight binary coded serial decimal numbers is reported. The converter of the invention in its basic form generally coded pulse words of a type having an algebraic sign digit followed serially by a plurality of decimal digits in order of decreasing significance preceding a y algebraic sign digit followed serially by a plurality of decimal digits in order of decreasing significance. A switching martix is coupled to said input circuit and is internally connected to produce serial straight binary coded pulse groups indicative of the excess-3 coded input. A stepping circuit is coupled to the switching matrix and to a synchronous counter having a plurality of x decimal digit and plurality of y decimal digit indicator terminals. The stepping circuit steps the counter in synchornism with the serial binary pulse group output from the switching matrix to successively produce pulses at corresponding ones of the x and y decimal digit indicator terminals. The combinations of straight binary coded pulse groups and corresponding decimal digit indicator signals so produced comprise a basic output suitable for application to a variety of output apparatus.

  3. Control for stabilizing the alignment position of the rotor of a synchronous motor

    DOEpatents

    Donley, Lawrence I.

    1988-01-01

    A method and apparatus for damping oscillations in the rotor load angle of a synchronous motor to provide stable rotational alignment in high precision applications. The damping method includes sensing the angular position of the rotor and utilizing the position signal to generate an error signal in response to changes in the period of rotation of the rotor. The error signal is coupled to phase shift amplifiers which shift the phase of the motor drive signal in a direction to damp out the oscillations in the rotor load angle.

  4. Control for stabilizing the alignment position of the rotor of the synchronous motor

    DOEpatents

    Donley, L.I.

    1985-03-12

    A method and apparatus is described for damping oscillations in the rotor load angle of a synchronous motor to provide stable rotational alignment in high precision applications. The damping method includes sensing the angular position of the rotor and utilizing the position signal to generate an error signal in response to changes in the period of rotation of the rotor. The error signal is coupled to phase shift amplifiers which shift the phase of the motor drive signal in a direction to damp out the oscillations in the rotor load angle.

  5. Improvements of Power Factor and Torque of a Synchronous Reluctance Motor with a Slit Rotor

    NASA Astrophysics Data System (ADS)

    Nashiki, Masayuki; Inoue, Yoshimitu; Kawai, Youichi; Yokochi, Takanori; Satake, Akiyoshi; Okuma, Shigeru

    Power factor and torque of synchronous reluctance motors with a slit rotor are studied. In there stators, divided teeth made of powder magnetic core are adopted and windings are improved to get high space factor of stator windings and to shorten coil ends. In there rotors, stainless sheets are inserted among soft magnetic metal sheets with adhesive to strengthen the rotors and rotor structure is improved to enlarge the saliency ratio (Ld/Lq). As the result, the power factor 0.78 and 1.6 times torque at same motor size are attained.

  6. Variable speed induction motor operation from a 20-kHz power bus

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1989-01-01

    Induction motors are recognized for their simple rugged construction to date, however, their application to variable speed or servo drives has been hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation offrequency and voltage allows independent control of rotor and stator flux, full four-quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.

  7. Variable speed induction motor operation from a 20-kHz power bus

    NASA Astrophysics Data System (ADS)

    Hansen, Irving G.

    Induction motors are recognized for their simple rugged construction to date, however, their application to variable speed or servo drives has been hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation offrequency and voltage allows independent control of rotor and stator flux, full four-quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.

  8. Variable speed induction motor operation from a 20-kHz power bus

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1989-01-01

    Induction motors are recognized for their simple rugged construction. To date, however, their application to variable speed or servo drives was hampered by limitations on their control. Induction motor drives tend to be complex and to display troublesome low speed characteristics due in part to nonsinusoidal driving voltages. A technique was developed which involves direct synthesis of sinusoidal driving voltages from a high frequency power bus and independent control of frequency and voltages. Separation of frequency and voltage allows independent control of rotor and stator flux, full four quadrant operation, and instantaneous torque control. Recent test results, current status of the technology, and proposed aerospace applications will be discussed.

  9. Field oriented control of induction motors

    NASA Technical Reports Server (NTRS)

    Burrows, Linda M.; Zinger, Don S.; Roth, Mary Ellen

    1990-01-01

    Induction motors have always been known for their simple rugged construction, but until lately were not suitable for variable speed or servo drives due to the inherent complexity of the controls. With the advent of field oriented control (FOC), however, the induction motor has become an attractive option for these types of drive systems. An FOC system which utilizes the pulse population modulation method to synthesize the motor drive frequencies is examined. This system allows for a variable voltage to frequency ratio and enables the user to have independent control of both the speed and torque of an induction motor. A second generation of the control boards were developed and tested with the next point of focus being the minimization of the size and complexity of these controls. Many options were considered with the best approach being the use of a digital signal processor (DSP) due to its inherent ability to quickly evaluate control algorithms. The present test results of the system and the status of the optimization process using a DSP are discussed.

  10. Lyapunov exponent for aging process in induction motor

    NASA Astrophysics Data System (ADS)

    Bayram, Duygu; Ünnü, Sezen Yıdırım; Şeker, Serhat

    2012-09-01

    focused on the controlling the mechanical parameters of the electrical machines. Brushless DC motor (BLDCM) and the other general purpose permanent magnet (PM) motors are the most widely examined motors [1, 8, 9]. But the researches, about Lyapunov Exponent, subjected to the induction motors are mostly focused on the control theory of the motors. Flux estimation of rotor, external load disturbances and speed tracking and vector control position system are the main research areas for induction motors [10, 11, 12-14]. For all the data sets which can be collected from an induction motor, vibration data have the key role for understanding the mechanical behaviours like aging, bearing damage and stator insulation damage [15-18]. In this paper aging of an induction motor is investigated by using the vibration signals. The signals consist of new and aged motor data. These data are examined by their 2 dimensional phase portraits and the geometric interpretation is applied for detecting the Lyapunov Exponents. These values are compared in order to define the character and state estimation of the aging processes.

  11. Vibration Analysis of AN Induction Motor

    NASA Astrophysics Data System (ADS)

    WANG, C.; LAI, J. C. S.

    1999-07-01

    With the advent of power electronics, variable speed induction motors are finding increasing use in industries because of their low cost and potential savings in energy consumption. However, the acoustic noise emitted by the motor increases due to switching harmonics introduced by the electronic inverters. Consequently, the vibro-acoustic behaviour of the motor structure has attracted more attention. In this paper, considerations given to modelling the vibration behaviour of a 2·2 kW induction motor are discussed. By comparing the calculated natural frequencies and the mode shapes with the results obtained from experimental modal testing, the effects of the teeth of the stator, windings, outer casing, slots, end-shields and support on the overall vibration behaviour are analyzed. The results show that when modelling the vibration behaviour of a motor structure, the laminated stator should be treated as an orthotropic structure, and the teeth of the stator could be neglected. As the outer casing, end-shields and the support all affect the vibration properties of the whole structure, these substructures should be incorporated in the model to improve the accuracy.

  12. Investigation of a rotary ultrasonic motor using a longitudinal vibrator and spiral fin rotor.

    PubMed

    Peng, Taijiang; Wu, Xiaoyu; Liang, Xiong; Shi, Hongyan; Luo, Feng

    2015-08-01

    A Langevin transducer can provide longitudinal vibration with larger amplitude while also possessing a greater fatigue life than other types of piezoelectric vibrators. A novel rotary Ultrasonic Motor (USM) was proposed based on the use of a longitudinal transducer (acting as the stator) and a spiral fin rotor: the front cover of the Langevin transducer was designed as a double-layer cup-shaped structure, with the rotor sustained by the inner-layer, and the bearing cover fixed to the outer-layer; the rotor consisted of a shaft and spiral fins which acted as the elastic coupler. It is different from a traditional traveling USM, because the stator provides longitudinal vibration and the rotor generates the elliptical motion. This paper analyzed the motion locus equation of the fin contact points. Additionally, a theoretical analysis was performed in regards to the mechanism and the motor's rotor motion characteristics, which demonstrates the relationships among the motor's driving force, the torque, the revolution speed, and the motor structure parameters. A motor prototype has been manufactured and surveyed to demonstrate the motor performance. The relationships between the amplitude and the preload on the rotor, the free revolution speed, and the torque of the motor have also been studied.

  13. Adaptive speed/position control of induction motor based on SPR approach

    NASA Astrophysics Data System (ADS)

    Lee, Hou-Tsan

    2014-11-01

    A sensorless speed/position tracking control scheme for induction motors is proposed subject to unknown load torque via adaptive strictly positive real (SPR) approach design. A special nonlinear coordinate transform is first provided to reform the dynamical model of the induction motor. The information on rotor fluxes can thus be derived from the dynamical model to decide on the proportion of input voltage in the d-q frame under the constraint of the maximum power transfer property of induction motors. Based on the SPR approach, the speed and position control objectives can be achieved. The proposed control scheme is to provide the speed/position control of induction motors while lacking the knowledge of some mechanical system parameters, such as the motor inertia, motor damping coefficient, and the unknown payload. The adaptive control technique is thus involved in the field oriented control scheme to deal with the unknown parameters. The thorough proof is derived to guarantee the stability of the speed and position of control systems of induction motors. Besides, numerical simulation and experimental results are also provided to validate the effectiveness of the proposed control scheme.

  14. A thermal network model for induction motors of hermetic reciprocating compressors

    NASA Astrophysics Data System (ADS)

    Dutra, T.; Deschamps, C. J.

    2015-08-01

    This paper describes a simulation model for small reciprocating compressors with emphasis on the electrical motor modelling. Heat transfer is solved through algebraic equations derived from lumped thermal energy balances applied to the compressor components. Thermal conductances between the motor components are characterized via a thermal network model. The single-phase induction motor is modelled via an equivalent circuit, allowing predictions for the motor performance and distributed losses. The predicted temperature distribution is used to evaluate the stator and rotor windings resistances. The thermal and electric models are solved in a coupled manner with a model for the compression cycle. Predictions of temperature distribution, motor efficiency, as well as isentropic and volumetric efficiencies, are compared with experimental data at different operating conditions. The model is then applied to analyse the motor temperature as a function of input voltage and stator wire diameter.

  15. Induction generator-induction motor wind-powered pumping system

    SciTech Connect

    Miranda, M.S.; Lyra, R.O.C.; Silva, S.R.

    1997-12-31

    The energy storage matter plays an important role in wind-electric conversion systems for isolated applications. Having that in mind, two different approaches can be basically considered: either the immediate conversion of the generated electric energy, as in a water pumping system or electric energy storage for later use, as in a battery charging system. Due to some features such as no need of an external reactive power source and, sometimes, a gearbox, permanent-magnet synchronous generators have been broadly used in low rated power isolated systems. Despite that, system performance can be affected when the generator is feeding an inductive load (e.g., an induction motor) under variable-speed-variable-frequency operational conditions. Since there is no effective flux control, motor overload may occur at high wind speeds. Thus, good system performance can be obtained through additional control devices which may increase system cost. Although being rugged and cheap, induction machines always work as a reactive power drain; therefore, they demand an external reactive power source. Considering that, reactive static compensators appear as an attractive alternative to the cost x performance problem. In addition to that, different control strategies can be used so that system performance can be improved.

  16. Stability analysis of the rotor of ultrasonic motor driving fluid directly.

    PubMed

    Changliang, Xia; Mengli, Wang

    2005-06-01

    The stability of the rotor of ultrasonic motor driving fluid directly is a key to its applications and control. This paper introduced the acoustic streaming and acoustic viscous stress near the boundary layer. Following this, the effect of acoustic viscous force on the stability of the rotor of ultrasonic motor driving fluid directly was presented in detail. The result showed that this system can be equivalent to a mass-spring and the spring constant can be used to weigh the stability of the rotor. By this model and relevant experiments, factors that affect the stability of the rotor such as the driving frequency, the rotor's weight and radius, the saturated acoustic streaming velocity, the mode number of stator vibration, the fluid's height and type are investigated and useful guidelines for design and application are obtained.

  17. Induction motors with minimum waste of magnetic iron

    NASA Astrophysics Data System (ADS)

    Boyko, Y. P.; Makarov, F. K.; Kremeshnyy, Y. A.; Stepanyants, E. A.

    1984-11-01

    An induction motor with minimum waste of magnetic iron has been developed. The stator core is made of silicon-iron steel strip, its width equal to the core height, and wound on edge to form a stack. Stator slots closed on the bore side and open on the outside for winding are formed together with teeth separating them by corrugating a silicon-iron steel strip of width equal to the stack length and sliding it, after winding, inside the core with an insulation interlayer between them. The thickness of this interlayer does not exceed 20% of the air gap between stator and rotor, but even this degrades motor starting and running performance. The performance is also degraded by leakage of magnetic flux through the slot bridge on the bore side and by nonuniformity of the air gap width resulting from corrugation of the stator bore surface. These drawbacks are partly compensated by lining the slots with film insulation instead of sleeves or tubes, thus making more slot space available for copper. Prototypes were built with 0.5 mm thick strip of 2212 steel for the teeth and strip of 08KP steel for the core, separated by a 0.03 mm layer of EKD-14 epoxy compound, with the air gap correspondingly narrowed from 0.25 to 0.2 mm. The stator winding is a singlelayer one of enamelled and triple vinyl-covered 0.67/0.73 mm copper wire, the slots insulated with Dacron film.

  18. Fuzzy efficiency optimization of AC induction motors

    NASA Technical Reports Server (NTRS)

    Jani, Yashvant; Sousa, Gilberto; Turner, Wayne; Spiegel, Ron; Chappell, Jeff

    1993-01-01

    This paper describes the early states of work to implement a fuzzy logic controller to optimize the efficiency of AC induction motor/adjustable speed drive (ASD) systems running at less than optimal speed and torque conditions. In this paper, the process by which the membership functions of the controller were tuned is discussed and a controller which operates on frequency as well as voltage is proposed. The membership functions for this dual-variable controller are sketched. Additional topics include an approach for fuzzy logic to motor current control which can be used with vector-controlled drives. Incorporation of a fuzzy controller as an application-specific integrated circuit (ASIC) microchip is planned.

  19. Synchronous motor with soft start element formed between the motor rotor and motor output shaft to successfully synchronize loads that have high inertia and/or high torque

    DOEpatents

    Umans, Stephen D; Nisley, Donald L; Melfi, Michael J

    2014-10-28

    A line-start synchronous motor has a housing, a rotor shaft, and an output shaft. A soft-start coupling portion is operatively coupled to the output shaft and the rotor shaft. The soft-start coupling portion is configurable to enable the synchronous motor to obtain synchronous operation and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling. The synchronous motor is sufficiently rated to obtain synchronous operation and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling.

  20. Prediction and analysis of magnetic forces in permanent magnet brushless dc motor with rotor eccentricity

    NASA Astrophysics Data System (ADS)

    Liu, Z. J.; Li, J. T.; Jabbar, M. A.

    2006-04-01

    In design of permanent magnet motors for high-precision applications, it is sometimes necessary, early in the design stage, to have a detailed analysis of the effect of rotor eccentricity that may result from manufacturing imperfectness or use of fluid dynamic or aerodynamic bearings. This paper presents an analytical model for electromagnetic torque and forces in permanent magnet motors with rotor eccentricity. The model gives an insight to the relationship between the effect of the eccentricity and the other motor design parameters on the electromagnetic forces. It is shown that the calculated magnetic forces obtained from this model agree well with those obtained from numerical simulations that are very computationally demanding.

  1. Fault detection and diagnosis of induction motors using motor current signature analysis and a hybrid FMM-CART model.

    PubMed

    Seera, Manjeevan; Lim, Chee Peng; Ishak, Dahaman; Singh, Harapajan

    2012-01-01

    In this paper, a novel approach to detect and classify comprehensive fault conditions of induction motors using a hybrid fuzzy min-max (FMM) neural network and classification and regression tree (CART) is proposed. The hybrid model, known as FMM-CART, exploits the advantages of both FMM and CART for undertaking data classification and rule extraction problems. A series of real experiments is conducted, whereby the motor current signature analysis method is applied to form a database comprising stator current signatures under different motor conditions. The signal harmonics from the power spectral density are extracted as discriminative input features for fault detection and classification with FMM-CART. A comprehensive list of induction motor fault conditions, viz., broken rotor bars, unbalanced voltages, stator winding faults, and eccentricity problems, has been successfully classified using FMM-CART with good accuracy rates. The results are comparable, if not better, than those reported in the literature. Useful explanatory rules in the form of a decision tree are also elicited from FMM-CART to analyze and understand different fault conditions of induction motors.

  2. Induction machine condition monitoring using notch-filtered motor current

    NASA Astrophysics Data System (ADS)

    Günal, Serkan; Gökhan Ece, Dog˜an; Nezih Gerek, Ömer

    2009-11-01

    This paper presents a new approach to induction motor condition monitoring using notch-filtered motor current signature analysis (NFMCSA). Unlike most of the previous work utilizing motor current signature analysis (MCSA) using spectral methods to extract required features for detecting motor fault conditions, here NFMCSA is performed in time-domain to extract features of energy, sample extrema, and third and fourth cumulants evaluated from data within sliding time window. Six identical three-phase induction motors were used for the experimental verification of the proposed method. One healthy machine was used as a reference, while other five with different synthetic faults were used for condition detection and classification. Extracted features obtained from NFMCSA of all motors were employed in three different and popular classifiers. The proposed motor current analysis and the performance of the features used for fault detection and classification are examined at various motor load levels and it is shown that a successful induction motor condition monitoring system is developed. Developed system is also able to indicate the load level and the type of a fault in multi-dimensional feature space representation. In order to test the generality and applicability of the developed method to other induction motors, data acquired from another healthy induction motor with different number of poles and rated power is also incorporated into the system. In spite of the above difference, the proposed feature set successfully locates the healthy motor within the classification cluster of "healthy motors" on the feature space.

  3. Induction Motor Drive System Based on Linear Active Disturbance Rejection Controller

    NASA Astrophysics Data System (ADS)

    Liu, Liying; Zhang, Yongli; Yao, Qingmei

    It is difficult to establish an exact mathematical model for the induction motor and the robustness is poor of the vector control system using PI regulator. This paper adopts the linear active disturbance rejection controller (LADRC) to control inductor motor. LADRC doesn't need the exact mathematical model of motor and it can not only estimate but also compensate the general disturbance that includes the coupling items in model of motor and parameters perturbations by linear extended state observer (LESO), so the rotor flux and torque fully decouple. As a result, the performance is improved. To prove the above control scheme, the proposed control system has been simulated in MATLAB/SIMULINK, and the comparison was made with PID. Simulation results show that LADRC' has better performance and robustness than PID.

  4. A novel PM motor with hybrid PM excitation and asymmetric rotor structure for high torque performance

    PubMed Central

    Xu, Gaohong; Liu, Guohai; Du, Xinxin; Bian, Fangfang

    2017-01-01

    This paper proposes a novel permanent magnet (PM) motor for high torque performance, in which hybrid PM material and asymmetric rotor design are applied. The hybrid PM material is adopted to reduce the consumption of rare-earth PM because ferrite PM is assisted to enhance the torque production. Meanwhile, the rotor structure is designed to be asymmetric by shifting the surface-insert PM (SPM), which is used to improve the torque performance, including average torque and torque ripple. Moreover, the reasons for improvement of the torque performance are explained by evaluation and analysis of the performances of the proposed motor. Compared with SPM motor and V-type motor, the merit of high utilization ratio of rare-earth PM is also confirmed, showing that the proposed motor can offer higher torque density and lower torque ripple simultaneously with less consumption of rare-earth PM. PMID:28382228

  5. Counteracting Rotor Imbalance in a Bearingless Motor System with Feedforward Control

    NASA Technical Reports Server (NTRS)

    Kascak, Peter Eugene; Jansen, Ralph H.; Dever, Timothy; Nagorny, Aleksandr; Loparo, Kenneth

    2012-01-01

    In standard motor applications, traditional mechanical bearings represent the most economical approach to rotor suspension. However, in certain high performance applications, rotor suspension without bearing contact is either required or highly beneficial. Such applications include very high speed, extreme environment, or limited maintenance access applications. This paper extends upon a novel bearingless motor concept, in which full five-axis levitation and rotation of the rotor is achieved using two motors with opposing conical air-gaps. By leaving the motors' pole-pairs unconnected, different d-axis flux in each pole-pair is created, generating a flux imbalance which creates lateral force. Note this is approach is different than that used in previous bearingless motors, which use separate windings for levitation and rotation. This paper will examine the use of feedforward control to counteract synchronous whirl caused by rotor imbalance. Experimental results will be presented showing the performance of a prototype bearingless system, which was sized for a high speed flywheel energy storage application, with and without feedforward control.

  6. Torque ripple minimization in a doubly salient permanent magnet motors by skewing the rotor teeth

    NASA Astrophysics Data System (ADS)

    Sheth, N. K.; Sekharbabu, A. R. C.; Rajagopal, K. R.

    2006-09-01

    This paper presents the effects of skewing the rotor teeth on the performance of an 8/6 doubly salient permanent magnet motor using a simple method, which utilizes the results obtained from the 2-D FE analysis. The optimum skewing angle is obtained as 12-15° for the least ripple torque without much reduction in the back-emf.

  7. Torsional stress analysis of the squirrel-cage rotor for three phase asynchronous motors

    NASA Astrophysics Data System (ADS)

    Axinte, T.; Nutu, C.

    2015-11-01

    The paper aims to determine the torsional stress occurring in the rotor's shaft of the three phase asynchronous motors for a given rotational speed of the rotor. The three phase asynchronous motor is started using the main starting variants, each variant having its own torque characteristic which produces a certain maximum shear stress. The model uses several hypotheses regarding the geometry of the domain, the dynamic behavior, the friction phenomenon and the mass of the shaft which is disregarded in a model and it is considered in a more accurate model. The maximum shear stress is produced by the shock which occurs in the starting process of the motors. This maximum stress may lead to the failure of the rotor either because it breaks, or because of the fatigue of the material produced by frequent starting of the motor. Information resulted from this study are useful for the selection of the appropriate material, of the according geometry of the design and elaboration of the specifications for the in-service use of the motor.This theoretical study will be followed by the development of more accurate models which will also include experimental studies employed to calibrate the theoretical models and to verify their accuracy.

  8. Speed Sensorless Induction Motor Drives for Electrical Actuators: Schemes, Trends and Tradeoffs

    NASA Technical Reports Server (NTRS)

    Elbuluk, Malik E.; Kankam, M. David

    1997-01-01

    For a decade, induction motor drive-based electrical actuators have been under investigation as potential replacement for the conventional hydraulic and pneumatic actuators in aircraft. Advantages of electric actuator include lower weight and size, reduced maintenance and operating costs, improved safety due to the elimination of hazardous fluids and high pressure hydraulic and pneumatic actuators, and increased efficiency. Recently, the emphasis of research on induction motor drives has been on sensorless vector control which eliminates flux and speed sensors mounted on the motor. Also, the development of effective speed and flux estimators has allowed good rotor flux-oriented (RFO) performance at all speeds except those close to zero. Sensorless control has improved the motor performance, compared to the Volts/Hertz (or constant flux) controls. This report evaluates documented schemes for speed sensorless drives, and discusses the trends and tradeoffs involved in selecting a particular scheme. These schemes combine the attributes of the direct and indirect field-oriented control (FOC) or use model adaptive reference systems (MRAS) with a speed-dependent current model for flux estimation which tracks the voltage model-based flux estimator. Many factors are important in comparing the effectiveness of a speed sensorless scheme. Among them are the wide speed range capability, motor parameter insensitivity and noise reduction. Although a number of schemes have been proposed for solving the speed estimation, zero-speed FOC with robustness against parameter variations still remains an area of research for speed sensorless control.

  9. An Induction Motor Based Wind Turbine Emulator

    NASA Astrophysics Data System (ADS)

    Sokolovs, A.; Grigans, L.; Kamolins, E.; Voitkans, J.

    2014-04-01

    The authors present a small-scale wind turbine emulator based on the AC drive system and discuss the methods for power coefficient calculation. In the work, the experimental set-up consisting of an AC induction motor, a frequency converter, a synchronous permanent magnet generator, a DC-DC boost converter and DC load was simulated and tested using real-life equipment. The experimentally obtained wind turbine power and torque diagrams using the emulator are in a good agreement with the theoretical ones. Šajā rakstā parādīta mazas jaudas vēja turbīnas emulatora izveide ar maiņstrāvas piedziņas sistēmu, kā arī analizētas vairākas turbīnas jaudas koeficienta analītiskās aprēķina metodes. Vēja turbīnas emulatora eksperimentālais stends, kas sastāv no asinhronā elektromotora, frekvenču pārveidotāja, sinhronā pastāvīgo magnētu ģeneratora, līdzstrāvas paaugstinošā pārveidotāja un slodzes, tika pārbaudīts gan simulēšanas vidē, gan uz reālām iekārtām. Eksperimentāli iegūtās vēja turbīnas emulatora jaudas un momenta diagrammas ir salīdzinātas ar teorētiskajām.

  10. Primary control of a Mach scale swashplateless rotor using brushless DC motor actuated trailing edge flaps

    NASA Astrophysics Data System (ADS)

    Saxena, Anand

    The focus of this research was to demonstrate a four blade rotor trim in forward flight using integrated trailing edge flaps instead of using a swashplate controls. A compact brushless DC motor was evaluated as an on-blade actuator, with the possibility of achieving large trailing edge flap amplitudes. A control strategy to actuate the trailing edge flap at desired frequency and amplitude was developed and large trailing edge flap amplitudes from the motor (instead of rotational motion) were obtained. Once the actuator was tested on the bench-top, a lightweight mechanism was designed to incorporate the motor in the blade and actuate the trailing edge flaps. A six feet diameter, four bladed composite rotor with motor-flap system integrated into the NACA 0012 airfoil section was fabricated. Systematic testing was carried out for a range of load conditions, first in the vacuum chamber followed by hover tests. Large trailing edge flap deflections were observed during the hover testing, and a peak to peak trailing edge flap amplitude of 18 degree was achieved at 2000 rotor RPM with hover tip Mach number of 0.628. A closed loop controller was designed to demonstrate trailing edge flap mean position and the peak to peak amplitude control. Further, a soft pitch link was designed and fabricated, to replace the stiff pitch link and thereby reduce the torsional stiffness of the blade to 2/rev. This soft pitch link allowed for blade root pitch motion in response to the trailing edge flap inputs. Blade pitch response due to both steady as well as sinusoidal flap deflections were demonstrated. Finally, tests were performed in Glenn L. Martin wind tunnel using a model rotor rig to assess the performance of motor-flap system in forward flight. A swashplateless trim using brushless DC motor actuated trailing edge flaps was achieved for a rotor operating at 1200 RPM and an advance ratio of 0.28. Also, preliminary exploration was carried out to test the scalability of the motor

  11. Control system for an induction motor with energy recovery

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A control circuit for an induction motor powered system is disclosed in which a power factor controlled servo loop is used to control, via the phase angle of firing of a triac, the power input to the motor, as a function of load placed on the motor by machinery of the powered system. Then, upon application of torque by this machinery to the motor, which tends to overspeed the motor, the firing angle of the triac is automatically set to a fixed, and relatively short, firing angle.

  12. Performance Analysis of Saturated Induction Motors by Virtual Tests

    ERIC Educational Resources Information Center

    Ojaghi, M.; Faiz, J.; Kazemi, M.; Rezaei, M.

    2012-01-01

    Many undergraduate-level electrical machines textbooks give detailed treatments of the performance of induction motors. Students can deepen this understanding of motor performance by performing the appropriate practical work in laboratories or in simulation using proper software packages. This paper considers various common and less-common tests…

  13. Power factor control system for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1981-01-01

    A power control circuit for an induction motor is disclosed in which a servo loop is used to control power input by controlling the power factor of motor operation. The power factor is measured by summing the voltage and current derived square wave signals.

  14. Axial-Gap Induction Motor For Levitated Specimens

    NASA Technical Reports Server (NTRS)

    Sridharan, Govind; Rhim, Won-Kyu; Barber, Dan; Chung, Sang

    1992-01-01

    Motor does not obscure view of specimen. Axial-gap induction motor applies torque to rotate electrostatically or electromagnetically levitated specimen of metal. Possible applications include turning specimens for uniform heating under focused laser beams and obtaining indirect measurements of resistivities or of surface tensions in molten specimens.

  15. Indirect rotor position sensing in real time for brushless permanent magnet motor drives

    SciTech Connect

    Ertugrul, N.; Acarnley, P.P.

    1998-07-01

    This paper describes a modern solution to real-time rotor position estimation of brushless permanent magnet (PM) motor drives. The position estimation scheme, based on flux linkage and line-current estimation, is implemented in real time by using the abc reference frame, and it is tested dynamically. The position estimation model of the test motor, development of hardware, and basic operation of the digital signal processor (DSP) are discussed. The overall position estimation strategy is accomplished with a fast DSP (TMS320C30). The method is a shaft position sensorless method that is applicable to a wide range of excitation types in brushless PM motors without any restriction on the motor model and the current excitation. Both rectangular and sinewave-excited brushless PM motor drives are examined, and the results are given to demonstrate the effectiveness of the method with dynamic loads in closed estimated position loop.

  16. Analysis of Magnetic Properties on the Outer Rotor Type Hybrid Stepping Motors Using 3D Finite Element Method

    NASA Astrophysics Data System (ADS)

    Enomoto, Yuji; Miyata, Kenji; Oonishi, Kazuo; Motegi, Yasuaki

    The three-dimensional magnetic field analysis has clarified the effect of several structural and manufacturing factors on the properties of the outer rotor type stepping motors. (1) The number of rotor teeth, 128, can make a unit step angle under 0.5 degree and a cogging torque under 1mNm for the outer rotor type stepping motor with the outer diameter under 60mm and with the output torque above 0.4Nm. (2) The permanent magnet flux has an optimal value dependent on the thickness of the laminated core to maximize the motor torque. (3) The lamination stacking error of the small teeth of the rotor and stator has a large effect on the cogging torque of the stepping motor.

  17. Electric propulsion using the permanent magnet synchronous motor without rotor position transducers

    NASA Astrophysics Data System (ADS)

    Batzel, Todd Douglas

    The permanent magnet synchronous motor (PMSM) is increasingly playing an important role in electric propulsion systems due to its many advantages over competing technologies. For successful operation of the PMSM, rotor position and speed information is required. A resolver or encoder attached to the shaft of the machine usually provides this information. Many applications, however, cannot tolerate the use of the position sensor because of space and weight limitations, reliability concerns, or packaging issues. Thus, there has been an intense interest in the development of a so-called position sensorless drive, where the PMSM stator itself is used as the rotor position sensor. In this work, a sensorless electric drive is developed for various undersea propulsion applications, where the rotor position sensor is often undesirable due to the harsh operating environment as well as space and weight limitations. In this work, an observer is developed which enables sensorless operation of the PMSM over a wide speed range. In addition, a method is presented for estimating the standstill rotor angle, an operating condition at which the rotor position observers are typically ill conditioned. In this work two design methodologies are applied to the sensorless electric drive application, including a model-based and a neural network-based approach. Implementation issues for the sensorless electric drive are discussed, and experimental results are presented in order to demonstrate the effectiveness of the proposed techniques to the sensorless PMSM.

  18. MRAS state estimator for speed sensorless ISFOC induction motor drives with Luenberger load torque estimation.

    PubMed

    Zorgani, Youssef Agrebi; Koubaa, Yassine; Boussak, Mohamed

    2016-03-01

    This paper presents a novel method for estimating the load torque of a sensorless indirect stator flux oriented controlled (ISFOC) induction motor drive based on the model reference adaptive system (MRAS) scheme. As a matter of fact, this method is meant to inter-connect a speed estimator with the load torque observer. For this purpose, a MRAS has been applied to estimate the rotor speed with tuned load torque in order to obtain a high performance ISFOC induction motor drive. The reference and adjustable models, developed in the stationary stator reference frame, are used in the MRAS scheme in an attempt to estimate the speed of the measured terminal voltages and currents. The load torque is estimated by means of a Luenberger observer defined throughout the mechanical equation. Every observer state matrix depends on the mechanical characteristics of the machine taking into account the vicious friction coefficient and inertia moment. Accordingly, some simulation results are presented to validate the proposed method and to highlight the influence of the variation of the inertia moment and the friction coefficient on the speed and the estimated load torque. The experimental results, concerning to the sensorless speed with a load torque estimation, are elaborated in order to validate the effectiveness of the proposed method. The complete sensorless ISFOC with load torque estimation is successfully implemented in real time using a digital signal processor board DSpace DS1104 for a laboratory 3 kW induction motor.

  19. Motor power control circuit for ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A motor power control of the type which functions by controlling the power factor wherein one of the parameters of power factor current on time is determined by the on time of a triac through which current is supplied to the motor. By means of a positive feedback circuit, a wider range of control is effected.

  20. Transistorized PWM inverter-induction motor drive system

    NASA Technical Reports Server (NTRS)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  1. Flux-Based Deadbeat Control of Induction-Motor Torque

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Lorenz, Robert D.

    2003-01-01

    An improved method and prior methods of deadbeat direct torque control involve the use of pulse-width modulation (PWM) of applied voltages. The prior methods are based on the use of stator flux and stator current as state variables, leading to mathematical solutions of control equations in forms that do not lend themselves to clear visualization of solution spaces. In contrast, the use of rotor and stator fluxes as the state variables in the present improved method lends itself to graphical representations that aid in understanding possible solutions under various operating conditions. In addition, the present improved method incorporates the superposition of high-frequency carrier signals for use in a motor-self-sensing technique for estimating the rotor shaft angle at any speed (including low or even zero speed) without need for additional shaft-angle-measuring sensors.

  2. Motor technology for mining applications advances

    SciTech Connect

    Fiscor, S.

    2009-08-15

    AC motors are steadily replacing DC motors in mining and mineral processing equipment, requiring less maintenance. The permanent magnet rotor, or the synchronous motor, has enabled Blador to introduce a line of cooling tower motors. Synchronous motors are soon likely to take over from the induction motor. 1 photo.

  3. Dynamics of the interaction between the rotor and the induction zone

    NASA Astrophysics Data System (ADS)

    Mirzaei, Mahmood; Meyer Forsting, Alexander R.; Troldborg, Niels

    2016-09-01

    Traditionally met masts are used for power and load verifications. They are normally placed 2-4 rotor diameters ahead of the turbine. However in complex terrain this can lead to complex analysis of the effect of the terrain on the flow field. A nacelle mounted lidar can provide a better tool for wind field measurements in all terrains. Provided that the measurement is close enough to the rotor disc, the uncertainty in the flow field measurement can be reduced significantly. Therefore any complex terrain calibration and changes in the wind direction can be avoided. However, close distance lidar measurements are affected by the presence of the wind turbine, due to its induction zone. In this work, the dynamic coupling between changes in the wind turbine operating point and the velocities inside the induction zone is studied. Reynolds-Averaged Navier-Stokes (RANS) simulations are used to investigate this interaction. Thereafter, system identification is used to fit first order dynamic models to the simulation results. The parameters of the model are given for the turbine induction zone. These results possibly reduce the uncertainty in lidar measurements, arising from wind turbine blockage.

  4. Fault tolerant vector control of induction motor drive

    NASA Astrophysics Data System (ADS)

    Odnokopylov, G.; Bragin, A.

    2014-10-01

    For electric composed of technical objects hazardous industries, such as nuclear, military, chemical, etc. an urgent task is to increase their resiliency and survivability. The construction principle of vector control system fault-tolerant asynchronous electric. Displaying recovery efficiency three-phase induction motor drive in emergency mode using two-phase vector control system. The process of formation of a simulation model of the asynchronous electric unbalance in emergency mode. When modeling used coordinate transformation, providing emergency operation electric unbalance work. The results of modeling transient phase loss motor stator. During a power failure phase induction motor cannot save circular rotating field in the air gap of the motor and ensure the restoration of its efficiency at rated torque and speed.

  5. Bearing Fault Detection in Induction Motor-Gearbox Drivetrain

    NASA Astrophysics Data System (ADS)

    Cibulka, Jaroslav; Ebbesen, Morten K.; Robbersmyr, Kjell G.

    2012-05-01

    The main contribution in the hereby presented paper is to investigate the fault detection capability of a motor current signature analysis by expanding its scope to include the gearbox, and not only the induction motor. Detecting bearing faults outside the induction motor through the stator current analysis represents an interesting alternative to traditional vibration analysis. Bearing faults cause changes in the stator current spectrum that can be used for fault diagnosis purposes. A time-domain simulation of the drivetrain model is developed. The drivetrain system consists of a loaded single stage gearbox driven by a line-fed induction motor. Three typical bearing faults in the gearbox are addressed, i.e. defects in the outer raceway, the inner raceway, and the rolling element. The interaction with the fault is modelled by means of kinematical and mechanical relations. The fault region is modelled in order to achieve gradual loss and gain of contact. A bearing fault generates an additional torque component that varies at the specific bearing defect frequency. The presented dynamic electromagnetic dq-model of an induction motor is adjusted for diagnostic purpose and considers such torque variations. The bearing fault is detected as a phase modulation of the stator current sine wave at the expected bearing defect frequency.

  6. Multisensor fusion for induction motor aging analysis and fault diagnosis

    NASA Astrophysics Data System (ADS)

    Erbay, Ali Seyfettin

    Induction motors are the most commonly used electrical drives, ranging in power from fractional horsepower to several thousand horsepowers. Several studies have been conducted to identify the cause of failure of induction motors in industrial applications. Recent activities indicate a focus towards building intelligence into the motors, so that a continuous on-line fault diagnosis and prognosis may be performed. The purpose of this research and development was to perform aging studies of three-phase, squirrel-cage induction motors; establish a database of mechanical, electrical and thermal measurements from load testing of the motors; develop a sensor-fusion method for on-line motor diagnosis; and use the accelerated aging models to extrapolate to the normal aging regimes. A new laboratory was established at The University of Tennessee to meet the goals of the project. The accelerated aging and motor performance tests constitute a unique database, containing information about the trend characteristics of measured signatures as a function of motor faults. The various measurements facilitate enhanced fault diagnosis of motors and may be effectively utilized to increase the reliability of decision making and for the development of life prediction techniques. One of these signatures is the use of Multi-Resolution Analysis (MRA) using wavelets. Using MRA in trending different frequency bands has revealed that higher frequencies show a characteristic increase when the condition of a bearing is in question. This study effectively showed that the use of MRA in vibration signatures can identify a thermal degradation or degradation via electrical charge of the bearing, whereas other failure mechanisms, such as winding insulation failure, do not exhibit such characteristics. A motor diagnostic system, called the Intelligent Motor Monitoring System (IMMS) was developed in this research. The IMMS integrated the various mechanical, electrical and thermal signatures, and

  7. Field-Oriented Control Of Induction Motors

    NASA Technical Reports Server (NTRS)

    Burrows, Linda M.; Roth, Mary Ellen; Zinger, Don S.

    1993-01-01

    Field-oriented control system provides for feedback control of torque or speed or both. Developed for use with commercial three-phase, 400-Hz, 208-V, 5-hp motor. Systems include resonant power supply operating at 20 kHz. Pulse-population-modulation subsystem selects individual pulses of 20-kHz single-phase waveform as needed to synthesize three waveforms of appropriate lower frequency applied to three phase windings of motor. Electric actuation systems using technology currently being built to peak powers of 70 kW. Amplitude of voltage of effective machine-frequency waveform determined by momentary frequency of pulses, while machine frequency determined by rate of repetition of overall temporal pattern of pulses. System enables independent control of both voltage and frequency.

  8. Induction motor inter turn fault detection using infrared thermographic analysis

    NASA Astrophysics Data System (ADS)

    Singh, Gurmeet; Anil Kumar, T. Ch.; Naikan, V. N. A.

    2016-07-01

    Induction motors are the most commonly used prime movers in industries. These are subjected to various environmental, thermal and load stresses that ultimately reduces the motor efficiency and later leads to failure. Inter turn fault is the second most commonly observed faults in the motors and is considered the most severe. It can lead to the failure of complete phase and can even cause accidents, if left undetected or untreated. This paper proposes an online and non invasive technique that uses infrared thermography, in order to detect the presence of inter turn fault in induction motor drive. Two methods have been proposed that detect the fault and estimate its severity. One method uses transient thermal monitoring during the start of motor and other applies pseudo coloring technique on infrared image of the motor, after it reaches a thermal steady state. The designed template for pseudo-coloring is in acquiescence with the InterNational Electrical Testing Association (NETA) thermographic standard. An index is proposed to assess the severity of the fault present in the motor.

  9. Improvement of the efficiency of induction motors

    NASA Astrophysics Data System (ADS)

    Falk, K.; Schoerner, J.

    1982-07-01

    The electric motor as energy converter was studied for four groups of parameters: process, network, foundations, and environment. The feasibility of reducing the losses of asynchronous three phase motors with squirrel cage or with slip rings in the power output range from 100 to 1500kW, was investigated. Mechanical losses from the bearings, from air friction, and from fan electromagnetic losses in the iron and in the copper, and the most efficient way of heat elimination due to this losses effect of a nonsinusoidal energy source on losses use of electronic controlled energy sources where variable load and speed are necessary, were studied. It is proved that for the studied motor range a better conception of ventilation is very useful and that the most efficient losses reduction are achieved by optimizing the electromagnetic design and the insulation techniques. Thyristor-based voltage regulators can achieve remarkable energy savings especially in the field of elevator technique in the speed range up to 2m/sec and in hoisting equipment.

  10. Implementation of a new fuzzy vector control of induction motor.

    PubMed

    Rafa, Souad; Larabi, Abdelkader; Barazane, Linda; Manceur, Malik; Essounbouli, Najib; Hamzaoui, Abdelaziz

    2014-05-01

    The aim of this paper is to present a new approach to control an induction motor using type-1 fuzzy logic. The induction motor has a nonlinear model, uncertain and strongly coupled. The vector control technique, which is based on the inverse model of the induction motors, solves the coupling problem. Unfortunately, in practice this is not checked because of model uncertainties. Indeed, the presence of the uncertainties led us to use human expertise such as the fuzzy logic techniques. In order to maintain the decoupling and to overcome the problem of the sensitivity to the parametric variations, the field-oriented control is replaced by a new block control. The simulation results show that the both control schemes provide in their basic configuration, comparable performances regarding the decoupling. However, the fuzzy vector control provides the insensitivity to the parametric variations compared to the classical one. The fuzzy vector control scheme is successfully implemented in real-time using a digital signal processor board dSPACE 1104. The efficiency of this technique is verified as well as experimentally at different dynamic operating conditions such as sudden loads change, parameter variations, speed changes, etc. The fuzzy vector control is found to be a best control for application in an induction motor.

  11. Methodology for fault detection in induction motors via sound and vibration signals

    NASA Astrophysics Data System (ADS)

    Delgado-Arredondo, Paulo Antonio; Morinigo-Sotelo, Daniel; Osornio-Rios, Roque Alfredo; Avina-Cervantes, Juan Gabriel; Rostro-Gonzalez, Horacio; Romero-Troncoso, Rene de Jesus

    2017-01-01

    Nowadays, timely maintenance of electric motors is vital to keep up the complex processes of industrial production. There are currently a variety of methodologies for fault diagnosis. Usually, the diagnosis is performed by analyzing current signals at a steady-state motor operation or during a start-up transient. This method is known as motor current signature analysis, which identifies frequencies associated with faults in the frequency domain or by the time-frequency decomposition of the current signals. Fault identification may also be possible by analyzing acoustic sound and vibration signals, which is useful because sometimes this information is the only available. The contribution of this work is a methodology for detecting faults in induction motors in steady-state operation based on the analysis of acoustic sound and vibration signals. This proposed approach uses the Complete Ensemble Empirical Mode Decomposition for decomposing the signal into several intrinsic mode functions. Subsequently, the frequency marginal of the Gabor representation is calculated to obtain the spectral content of the IMF in the frequency domain. This proposal provides good fault detectability results compared to other published works in addition to the identification of more frequencies associated with the faults. The faults diagnosed in this work are two broken rotor bars, mechanical unbalance and bearing defects.

  12. The effect of flagellar motor-rotor complexes on twitching motility in P. aeruginosa

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Utada, Andrew; Gibiansky, Maxsim; Xian, Wujing; Wong, Gerard

    2013-03-01

    P. aeruginosa is an opportunistic bacterium responsible for a broad range of biofilm infections. In order for biofilms to form, P. aeruginosa uses different types of surface motility. In the current understanding, flagella are used for swarming motility and type IV pili are used for twitching motility. The flagellum also plays important roles in initial surface attachment and in shaping the architectures of mature biofilms. Here we examine how flagella and pili interact during surface motility, by using cell tracking techniques. We show that the pili driven twitching motility of P. aeruginosa can be affected by the motor-rotor complexes of the flagellar system.

  13. Electromagnetic Radial Forces in a Hybrid Eight-Stator-Pole, Six-Rotor-Pole Bearingless Switched-Reluctance Motor

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.; Siebert, Mark W.; Ho, Eric J.

    2007-01-01

    Analysis and experimental measurement of the electromagnet force loads on the hybrid rotor in a novel bearingless switched-reluctance motor (BSRM) have been performed. A BSRM has the combined characteristics of a switched-reluctance motor and a magnetic bearing. The BSRM has an eight-pole stator and a six-pole hybrid rotor, which is composed of circular and scalloped lamination segments. The hybrid rotor is levitated using only one set of stator poles. A second set of stator poles imparts torque to the scalloped portion of the rotor, which is driven in a traditional switched reluctance manner by a processor. Analysis was done for nonrotating rotor poles that were oriented to achieve maximum and minimum radial force loads on the rotor. The objective is to assess whether simple one-dimensional magnetic circuit analysis is sufficient for preliminary evaluation of this machine, which may exhibit strong three-dimensional electromagnetic field behavior. Two magnetic circuit geometries, approximating the complex topology of the magnetic fields in and around the hybrid rotor, were employed in formulating the electromagnetic radial force equations. Reasonable agreement between the experimental results and the theoretical predictions was obtained with typical magnetic bearing derating factors applied to the predictions.

  14. Experimental method to reveal the effect of rotor magnet size and air gap on artificial heart driving motor torque and efficiency.

    PubMed

    Qian, K X; Yuan, H Y; Ru, W M; Zeng, P

    2002-01-01

    To investigate experimentally the effect of rotor magnet design on artificial heart driving motor performance, seven rotors with different magnet lengths or thicknesses, as well as different peripheral angles, were manufactured and tested in the same motor stator with different rotating speeds. The input power (voltage and current) and output torque were measured and the motor efficiency was computed. The results demonstrated that the reduction of rotor magnet size and the enlargement of the air gap between the rotor magnets and the stator coil core have no significant effect on motor efficiency, but will reduce the torque value on which the motor achieves the highest efficiency; it could be remedied however by increasing the rotating speed, because the torque at the high efficiency point will increase along with the rotating speed. These results may provide a basis for developing small rotor magnets, large air gap and high efficiency motors for driving an artificial heart pump.

  15. Using motors with a hollow rotor for the modulator of the light flux in polarimeters

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Nevodovskyi, P. V.

    2016-11-01

    Method of determining the degree of polarization of the light based on the transformation of parameters of the Stokes vector I = I{I0, Q, U, V} from the radiation source - in scalar. For the analysis of polarized light are used polaroids, prisms, gratings, etc. They are placed in front of the radiation detectors, and they can be static or rotating. The movable element of modulator (phase plate) can be rotated due to a kinematic transmission (by means of gear wheels etc.), or polarizing element can be mounted directly on the axis of rotation in the hole of the motor rotor. As these motors are used synchronous - a zero-moment electric and piezomotor.

  16. Different configurations of laser vibrometry for quality control of electric motors with external rotor

    NASA Astrophysics Data System (ADS)

    Chiariotti, P.; Ciarmatori, R.; Castellini, P.; Bastari, A.; Paone, N.

    2012-06-01

    When designing a test bench for vibration based diagnostics of machines with external rotating parts, such as electric motors having a rotating external rotor, one may choose among single point vibrometry, rotational vibrometry or in-plane vibrometry. The paper discusses these different options, taking the assumption that the minimum number of measuring instruments is preferred when instrumenting a quality control system and provides an insight into advantages and limitations of each instrument. In particular the following issues are discussed: a) possible installation lay-outs; b) alignment problems (and possible advantages for diagnostics), c) typical signals and diagnostic features which can be observed. The research presented refers to electric motors for home appliances, but potentially has wider application fields to other rotating machines.

  17. Metamodels for New Designs of Outer-Rotor Brushless Synchronous Electric Motors

    NASA Astrophysics Data System (ADS)

    Dirba, J.; Lavrinovicha, L.

    2014-04-01

    The authors consider the possibilities to synthesise metamodels for the analysis and optimisation of brushless synchronous motors. The metamodels are presented for new designs of the outer-rotor permanent magnet synchronous motor and the outer-rotor reluctance motor. The metamodels are synthesised based on the results obtained by the numerical calculations of magnetic field taking into account magnetic saturation. Analysis of the results for the motor magnetic field and tests of the metamodels at the selected and intermediate points shows that these can be synthesised with acceptable accuracy using numerical calculations instead of expensive real experiments. Rakstā ir apskatītas metamodeļu iegūšanas iespējas to izmantošanai bezkontaktu sinhrono dzinēju analīzē un optimizācijā. Ir iegūti metamodeļi sinhronam dzinējam ar pastāvīgajiem magnētiem un reaktīvam dzinējam ar ārējo rotoru. Sintezēto metamodeļu iegūšanai izmantoti elektrisko dzinēju magnētiskā lauka skaitlisko aprēķinu rezultāti, ievērojot magnētiskās ķēdes piesātinājumu. Metamodeļu pārbaude aprēķinu un starppunktos parādīja, ka to iegūšanai dārgo reālo eksperimentu vietā var izmantot magnētiskā lauka aprēķinu rezultātus.

  18. Development of a photo-voltaic pumping system using a brushless D.C. motor and helical rotor pump

    SciTech Connect

    Langridge, D.; Lawrance, W.; Wichert, B.

    1996-12-31

    A PV pumping system based on a brushless d.c. motor and helical rotor pump has been designed, simulated and a prototype constructed. The paper describes the operation of the system and the development of component models for the array, the brushless d.c. motor and helical rotor pump. Simulation results and subsequent test results for the complete system are included. Efficiencies of between 30 and 50% for the system (excluding the array) have been achieved over a range of loads and operating conditions for 4 x 1 and 4 x 2 array configurations. 9 refs., 10 figs., 2 tabs.

  19. Performance characteristics of three-phase induction motors

    NASA Technical Reports Server (NTRS)

    Wood, M. E.

    1977-01-01

    An investigation into the characteristics of three phase, 400 Hz, induction motors of the general type used on aircraft and spacecraft is summarized. Results of laboratory tests are presented and compared with results from a computer program. Representative motors were both tested and simulated under nominal conditions as well as off nominal conditions of temperature, frequency, voltage magnitude, and voltage balance. Good correlation was achieved between simulated and laboratory results. The primary purpose of the program was to verify the simulation accuracy of the computer program, which in turn will be used as an analytical tool to support the shuttle orbiter.

  20. An electric contact method to measure contact state between stator and rotor in a traveling wave ultrasonic motor.

    PubMed

    Qu, Jianjun; Zhou, Tieying

    2003-09-01

    Performances of ultrasonic motor (USM) depend considerably on contact state between stator and rotor. To measure the contact state in a traveling wave ultrasonic motor (TWUSM), a special test method is necessary. This paper develops a new method named electric contact method to measure contact state of stator and rotor in traveling wave type USM. The effects of pre-load and exciting voltage (amplitude) of stator on contact state between stator and rotor are studied with this method. By a simulating tester of friction properties of TWUSM, the variations of stalling torque and no-load speed against the pre-load and the exciting voltage have been measured. The relative contact length that describes the contact characteristic of stator and rotor is proposed. The relation between the properties of TWUSM and the contact state of stator and rotor are presented. Additionally, according to a theoretical contact model of stator and rotor in TWUSM, the contact lengths at given conditions are calculated and compared with the experimental results.

  1. Diagnosis of the three-phase induction motor using thermal imaging

    NASA Astrophysics Data System (ADS)

    Glowacz, Adam; Glowacz, Zygfryd

    2017-03-01

    Three-phase induction motors are used in the industry commonly for example woodworking machines, blowers, pumps, conveyors, elevators, compressors, mining industry, automotive industry, chemical industry and railway applications. Diagnosis of faults is essential for proper maintenance. Faults may damage a motor and damaged motors generate economic losses caused by breakdowns in production lines. In this paper the authors develop fault diagnostic techniques of the three-phase induction motor. The described techniques are based on the analysis of thermal images of three-phase induction motor. The authors analyse thermal images of 3 states of the three-phase induction motor: healthy three-phase induction motor, three-phase induction motor with 2 broken bars, three-phase induction motor with faulty ring of squirrel-cage. In this paper the authors develop an original method of the feature extraction of thermal images MoASoID (Method of Areas Selection of Image Differences). This method compares many training sets together and it selects the areas with the biggest changes for the recognition process. Feature vectors are obtained with the use of mentioned MoASoID and image histogram. Next 3 methods of classification are used: NN (the Nearest Neighbour classifier), K-means, BNN (the back-propagation neural network). The described fault diagnostic techniques are useful for protection of three-phase induction motor and other types of rotating electrical motors such as: DC motors, generators, synchronous motors.

  2. Evaluation of quasi-square wave inverter as a power source for induction motors

    NASA Technical Reports Server (NTRS)

    Guynes, B. V.; Haggard, R. L.; Lanier, J. R., Jr.

    1977-01-01

    The relative merits of quasi-square wave inverter-motor technology versus a sine wave inverter-motor system were investigated. The empirical results of several tests on various sizes of wye-wound induction motors are presented with mathematical analysis to support the conclusions of the study. It was concluded that, within the limitations presented, the quasi-square wave inverter-motor system is superior to the more complex sine wave system for most induction motor applications in space.

  3. Inductance and Active Phase Vector Based Torque Control for Switched Reluctance Motor Drives.

    NASA Astrophysics Data System (ADS)

    Kalpathi, Ramani Raman

    The Switched Reluctance Motor (SRM) drive technology has developed significantly over the last few years. The simplicity in both motor design and power converter requirement along with the availability of high frequency, high power semiconductor switches have made SRMs compete with conventional adjustable speed drive technologies. The subject of winding current control in switched reluctance machines has always been associated with the shaft position information. The use of inductance for direct commutation control is the central subject of this dissertation. In contrast to the conventional methods based on position commutation, new methods of control based on inductance commutation are presented. The object of a commutation algorithm is to switch the currents in the phase coils, in order to provide continuous energy conversion with maximum torque output for a given unit of input current. Since torque production in a SRM is based on the concept of variable reluctance, it makes more sense to observe the instantaneous phase inductance or reluctance instead of estimating the rotor position. The inductance sensors observe the machine parameters and provide sufficient information on the electrical characteristics of the coils. This control strategy avoids the inductance to position transformation blocks conventionally used in SRM control systems. In a typical SRM, the phase coils have a nonlinear behavior of inductance due to effects of current saturation. Also the parameters of one phase coil differ from those of the other due to manufacturing tolerances or due to bearing wear. In such cases, the algorithms written during the stage of manufacturing may not be valid after parameter changes. Optimizing torque production in the event of phase asymmetry and saturation is developed in this research. Indirect sensors connected to the active phase coil of the SRM are based on sensing the flux level in the active coil. New commutation algorithms based on flux sensing concepts

  4. Design comparison of single phase outer and inner-rotor hybrid excitation flux switching motor for hybrid electric vehicles

    NASA Astrophysics Data System (ADS)

    Mazlan, Mohamed Mubin Aizat; Sulaiman, Erwan; Husin, Zhafir Aizat; Othman, Syed Muhammad Naufal Syed; Khan, Faisal

    2015-05-01

    In hybrid excitation machines (HEMs), there are two main flux sources which are permanent magnet (PM) and field excitation coil (FEC). These HEMs have better features when compared with the interior permanent magnet synchronous machines (IPMSM) used in conventional hybrid electric vehicles (HEVs). Since all flux sources including PM, FEC and armature coils are located on the stator core, the rotor becomes a single piece structure similar with switch reluctance machine (SRM). The combined flux generated by PM and FEC established more excitation fluxes that are required to produce much higher torque of the motor. In addition, variable DC FEC can control the flux capabilities of the motor, thus the machine can be applied for high-speed motor drive system. In this paper, the comparisons of single-phase 8S-4P outer and inner rotor hybrid excitation flux switching machine (HEFSM) are presented. Initially, design procedures of the HEFSM including parts drawing, materials and conditions setting, and properties setting are explained. Flux comparisons analysis is performed to investigate the flux capabilities at various current densities. Then the flux linkages of PM with DC FEC of various DC FEC current densities are examined. Finally torque performances are analyzed at various armature and FEC current densities for both designs. As a result, the outer-rotor HEFSM has higher flux linkage of PM with DC FEC and higher average torque of approximately 10% when compared with inner-rotor HEFSM.

  5. Detection of stator winding faults in induction motors using three-phase current monitoring.

    PubMed

    Sharifi, Rasool; Ebrahimi, Mohammad

    2011-01-01

    The objective of this paper is to propose a new method for the detection of inter-turn short circuits in the stator windings of induction motors. In the previous reported methods, the supply voltage unbalance was the major difficulty, and this was solved mostly based on the sequence component impedance or current which are difficult to implement. Some other methods essentially are included in the offline methods. The proposed method is based on the motor current signature analysis and utilizes three phase current spectra to overcome the mentioned problem. Simulation results indicate that under healthy conditions, the rotor slot harmonics have the same magnitude in three phase currents, while under even 1 turn (0.3%) short circuit condition they differ from each other. Although the magnitude of these harmonics depends on the level of unbalanced voltage, they have the same magnitude in three phases in these conditions. Experiments performed under various load, fault, and supply voltage conditions validate the simulation results and demonstrate the effectiveness of the proposed technique. It is shown that the detection of resistive slight short circuits, without sensitivity to supply voltage unbalance is possible.

  6. Empirical mode decomposition and neural networks on FPGA for fault diagnosis in induction motors.

    PubMed

    Camarena-Martinez, David; Valtierra-Rodriguez, Martin; Garcia-Perez, Arturo; Osornio-Rios, Roque Alfredo; Romero-Troncoso, Rene de Jesus

    2014-01-01

    Nowadays, many industrial applications require online systems that combine several processing techniques in order to offer solutions to complex problems as the case of detection and classification of multiple faults in induction motors. In this work, a novel digital structure to implement the empirical mode decomposition (EMD) for processing nonstationary and nonlinear signals using the full spline-cubic function is presented; besides, it is combined with an adaptive linear network (ADALINE)-based frequency estimator and a feed forward neural network (FFNN)-based classifier to provide an intelligent methodology for the automatic diagnosis during the startup transient of motor faults such as: one and two broken rotor bars, bearing defects, and unbalance. Moreover, the overall methodology implementation into a field-programmable gate array (FPGA) allows an online and real-time operation, thanks to its parallelism and high-performance capabilities as a system-on-a-chip (SoC) solution. The detection and classification results show the effectiveness of the proposed fused techniques; besides, the high precision and minimum resource usage of the developed digital structures make them a suitable and low-cost solution for this and many other industrial applications.

  7. Empirical Mode Decomposition and Neural Networks on FPGA for Fault Diagnosis in Induction Motors

    PubMed Central

    Garcia-Perez, Arturo; Osornio-Rios, Roque Alfredo; Romero-Troncoso, Rene de Jesus

    2014-01-01

    Nowadays, many industrial applications require online systems that combine several processing techniques in order to offer solutions to complex problems as the case of detection and classification of multiple faults in induction motors. In this work, a novel digital structure to implement the empirical mode decomposition (EMD) for processing nonstationary and nonlinear signals using the full spline-cubic function is presented; besides, it is combined with an adaptive linear network (ADALINE)-based frequency estimator and a feed forward neural network (FFNN)-based classifier to provide an intelligent methodology for the automatic diagnosis during the startup transient of motor faults such as: one and two broken rotor bars, bearing defects, and unbalance. Moreover, the overall methodology implementation into a field-programmable gate array (FPGA) allows an online and real-time operation, thanks to its parallelism and high-performance capabilities as a system-on-a-chip (SoC) solution. The detection and classification results show the effectiveness of the proposed fused techniques; besides, the high precision and minimum resource usage of the developed digital structures make them a suitable and low-cost solution for this and many other industrial applications. PMID:24678281

  8. Development of a linear induction motor based artificial muscle system.

    PubMed

    Gruber, A; Arguello, E; Silva, R

    2013-01-01

    We present the design of a linear induction motor based on electromagnetic interactions. The engine is capable of producing a linear movement from electricity. The design consists of stators arranged in parallel, which produce a magnetic field sufficient to displace a plunger along its axial axis. Furthermore, the winding has a shell and cap of ferromagnetic material that amplifies the magnetic field. This produces a force along the length of the motor that is similar to that of skeletal muscle. In principle, the objective is to use the engine in the development of an artificial muscle system for prosthetic applications, but it could have multiple applications, not only in the medical field, but in other industries.

  9. Modelling and Analysis of Dual-Stator Induction Motors

    NASA Astrophysics Data System (ADS)

    Razik, Hubert; Rezzoug, Abderrezak; Hadiouche, Djafar

    In this paper, the analysis and the modelling of a Dual-Stator Induction Motor (DSIM) are presented. In particular, the effects of the shift angle between its three-phase windings are studied. A complex steady state model is first established in order to analyse its harmonic behavior when it is supplied by a non-sinusoidal voltage source. Then, a new transformation matrix is proposed to develop a suitable dynamic model. In both cases, the study is made using an arbitrary shift angle. Simulation results of its PWM control are also presented and compared in order to confirm our theoretical observations.

  10. NASTRAN buckling study of a linear induction motor reaction rail

    NASA Technical Reports Server (NTRS)

    Williams, J. G.

    1973-01-01

    NASTRAN was used to study problems associated with the installation of a linear induction motor reaction rail test track. Specific problems studied include determination of the critical axial compressive buckling stress and establishment of the lateral stiffness of the reaction rail under combined loads. NASTRAN results were compared with experimentally obtained values and satisfactory agreement was obtained. The reaction rail was found to buckle at an axial compressive stress of 11,400 pounds per square inch. The results of this investigation were used to select procedures for installation of the reaction rail.

  11. Effects of anisotropy on the performance characteristics of an axially laminated anisotropic-rotor synchronous reluctance motor drive system

    SciTech Connect

    Isaac, F.N.; Arkadan, A.A.; Russell, A.A.; El-Antably, A.

    1998-09-01

    In the last few years, increased attention has been paid to the performance characterization and evaluation of the performance of synchronous reluctance machines. Extensive research has concentrated on different rotor structures in order to achieve high performance variable speed drives for applications such as electric vehicles. The effects of accounting for anisotropy on the performance characteristics of Axially Laminated Anisotropic (ALA) rotor Synchronous Reluctance Motor (SynRM) drive systems are studied. These effects are evaluated from the simulations of a computer aided model. The model is based on the use of an iterative approach which indirectly couples a two dimensional (2D) nonlinear finite element (FE) model, which accounts for anisotropy, to a state space model describing the SynRM drive system. The simulation results are also validated by comparison to test data of a prototype ALA rotor SynRM drive system.

  12. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  13. Augmenting Plasticity Induction in Human Motor Cortex by Disinhibition Stimulation.

    PubMed

    Cash, Robin F H; Murakami, Takenobu; Chen, Robert; Thickbroom, Gary W; Ziemann, Ulf

    2016-01-01

    Cellular studies showed that disinhibition, evoked pharmacologically or by a suitably timed priming stimulus, can augment long-term plasticity (LTP) induction. We demonstrated previously that transcranial magnetic stimulation evokes a period of presumably GABA(B)ergic late cortical disinhibition (LCD) in human primary motor cortex (M1). Here, we hypothesized that, in keeping with cellular studies, LCD can augment LTP-like plasticity in humans. In Experiment 1, patterned repetitive TMS was applied to left M1, consisting of 6 trains (intertrain interval, 8 s) of 4 doublets (interpulse interval equal to individual peak I-wave facilitation, 1.3-1.5 ms) spaced by the individual peak LCD (interdoublet interval (IDI), 200-250 ms). This intervention (total of 48 pulses applied over ∼45 s) increased motor-evoked potential amplitude, a marker of corticospinal excitability, in a right hand muscle by 147% ± 4%. Control experiments showed that IDIs shorter or longer than LCD did not result in LTP-like plasticity. Experiment 2 indicated topographic specificity to the M1 hand region stimulated by TMS and duration of the LTP-like plasticity of 60 min. In conclusion, GABA(B)ergic LCD offers a powerful new approach for augmenting LTP-like plasticity induction in human cortex. We refer to this protocol as disinhibition stimulation (DIS).

  14. A new method of accurate broken rotor bar diagnosis based on modulation signal bispectrum analysis of motor current signals

    NASA Astrophysics Data System (ADS)

    Gu, F.; Wang, T.; Alwodai, A.; Tian, X.; Shao, Y.; Ball, A. D.

    2015-01-01

    Motor current signature analysis (MCSA) has been an effective way of monitoring electrical machines for many years. However, inadequate accuracy in diagnosing incipient broken rotor bars (BRB) has motivated many studies into improving this method. In this paper a modulation signal bispectrum (MSB) analysis is applied to motor currents from different broken bar cases and a new MSB based sideband estimator (MSB-SE) and sideband amplitude estimator are introduced for obtaining the amplitude at (1 ± 2 s)fs (s is the rotor slip and fs is the fundamental supply frequency) with high accuracy. As the MSB-SE has a good performance of noise suppression, the new estimator produces more accurate results in predicting the number of BRB, compared with conventional power spectrum analysis. Moreover, the paper has also developed an improved model for motor current signals under rotor fault conditions and an effective method to decouple the BRB current which interferes with that of speed oscillations associated with BRB. These provide theoretical supports for the new estimators and clarify the issues in using conventional bispectrum analysis.

  15. Prototype and estimation an ultrasonic motor using a transmission rod with a stator vibrator and a rotor at the both ends

    NASA Astrophysics Data System (ADS)

    Takano, Takehiro; Tamura, Hideki; Sato, Daisuke; Aoyagi, Manabu

    2012-05-01

    A new structure of ultrasonic motor composed of a stator vibrator, a rotor and an ultrasonic transmission rod is proposed. Two vibrations of a stator vibrator mounted at a rod end excite two orthogonal bending vibrations in the rod and elliptic motions of displacement are formed at another end of the rod. The elliptic motions produce a rotating force to a rotor pressed at the end. The simple structure of mounting and preloading a rotor is designed by FEM. It is checked experimentally that two orthogonal bending vibrations are excited in the rod and the motor operation of the new construction is confirmed.

  16. Dynamic Performance of Subway Vehicle with Linear Induction Motor System

    NASA Astrophysics Data System (ADS)

    Wu, Pingbo; Luo, Ren; Hu, Yan; Zeng, Jing

    The light rail vehicle with Linear Induction Motor (LIM) bogie, which is a new type of urban rail traffic tool, has the advantages of low costs, wide applicability, low noise, simple maintenance and better dynamic behavior. This kind of vehicle, supported and guided by the wheel and rail, is not driven by the wheel/rail adhesion force, but driven by the electromagnetic force between LIM and reaction plate. In this paper, three different types of suspensions and their characteristic are discussed with considering the interactions both between wheel and rail and between LIM and reaction plate. A nonlinear mathematical model of the vehicle with LIM bogie is set up by using the software SIMPACK, and the electromechanical model is also set up on Simulink roof. Then the running behavior of the LIM vehicle is simulated, and the influence of suspension on the vehicle dynamic performance is investigated.

  17. Induction motor control system with voltage controlled oscillator circuit

    NASA Technical Reports Server (NTRS)

    Nola, F. J.; Currie, J. R.; Reid, H., Jr. (Inventor)

    1973-01-01

    A voltage controlled oscillator circuit is reported in which there are employed first and second differential amplifiers. The first differential amplifier, being employed as an integrator, develops equal and opposite slopes proportional to an input voltage, and the second differential amplifier functions as a comparator to detect equal amplitude positive and negative selected limits and provides switching signals which gate a transistor switch. The integrating differential amplifier is switched between charging and discharging modes to provide an output of the first differential amplifier which upon the application of wave shaping provides a substantially sinusoidal output signal. A two phased version with a second integrator provides a second 90 deg phase shifted output for induction motor control.

  18. FUZZY-LOGIC-BASED CONTROLLERS FOR EFFICIENCY OPTIMIZATION OF INVERTER-FED INDUCTION MOTOR DRIVES

    EPA Science Inventory

    This paper describes a fuzzy-logic-based energy optimizing controller to improve the efficiency of induction motor/drives operating at various load (torque) and speed conditions. Improvement of induction motor efficiency is important not only from the considerations of energy sav...

  19. Neural and Fuzzy Adaptive Control of Induction Motor Drives

    SciTech Connect

    Bensalem, Y.; Sbita, L.; Abdelkrim, M. N.

    2008-06-12

    This paper proposes an adaptive neural network speed control scheme for an induction motor (IM) drive. The proposed scheme consists of an adaptive neural network identifier (ANNI) and an adaptive neural network controller (ANNC). For learning the quoted neural networks, a back propagation algorithm was used to automatically adjust the weights of the ANNI and ANNC in order to minimize the performance functions. Here, the ANNI can quickly estimate the plant parameters and the ANNC is used to provide on-line identification of the command and to produce a control force, such that the motor speed can accurately track the reference command. By combining artificial neural network techniques with fuzzy logic concept, a neural and fuzzy adaptive control scheme is developed. Fuzzy logic was used for the adaptation of the neural controller to improve the robustness of the generated command. The developed method is robust to load torque disturbance and the speed target variations when it ensures precise trajectory tracking with the prescribed dynamics. The algorithm was verified by simulation and the results obtained demonstrate the effectiveness of the IM designed controller.

  20. Fault analysis for condition monitoring of induction motors

    NASA Astrophysics Data System (ADS)

    Nandi, Subhasis

    Recently, research has picked up a fervent pace in the area of fault diagnosis of electrical machines. Like adjustable speed drives, fault prognosis has become almost indispensable. The manufacturers of these drives are now keen to include diagnostic features in the software to decrease machine down time and improve salability. Prodigious improvement in signal processing hardware and software has made this possible. Primarily, these techniques depend upon locating specific harmonic components in the line current, also known as motor current signature analysis (MCSA). These harmonic components are usually different for different types of faults. However, with multiple faults or different varieties of drive schemes, MCSA can become an onerous task as different types of faults and time harmonics may end up generating similar signatures. Thus, other signals such as speed, torque, noise, vibration, etc., are also explored for their frequency contents. Sometimes, altogether different techniques such as thermal measurements, chemical analysis, etc., are also employed to find out the nature and the degree of the fault. It is indeed evident that this area is vast in scope. Going by the present trend, human involvement in the actual fault detection decision making is slowly being replaced by automated tools such as expert systems, neural networks, fuzzy logic based systems; to name a few. However, this cannot be achieved without detailed fault analysis and subsequent recognition of the fault pattern. Keeping this in mind, simulation studies of the broken bar and eccentricity related faults using MCSA have been taken up. Also, a common theoretical basis for the different types (static, dynamic and mixed) of eccentricity related faults which give different signatures for different pole and rotor bar combinations has been developed. This will be of great importance both from fault diagnosis as well as sensorless drive applications' viewpoint. Finally, the insight gained from

  1. Field assessment of induction motor efficiency through air-gap torque

    SciTech Connect

    Hsu, J.S.; Sorenson, P.L.

    1995-11-01

    Induction motors are the most popular motors used in industry. This paper further suggests the use of air-gap torque method to evaluate their efficiency and load changes. The fundamental difference between Method E and the air-gap torque method is discussed. Efficiency assessments conducted on induction motors under various conditions show the accuracy and potential of the air-gap torque method.

  2. Variable frequency inverter for ac induction motors with torque, speed and braking control

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1975-01-01

    A variable frequency inverter was designed for driving an ac induction motor which varies the frequency and voltage to the motor windings in response to varying torque requirements for the motor so that the applied voltage amplitude and frequency are of optimal value for any motor load and speed requirement. The slip frequency of the motor is caused to vary proportionally to the torque and feedback is provided so that the most efficient operating voltage is applied to the motor. Winding current surge is limited and a controlled negative slip causes motor braking and return of load energy to a dc power source.

  3. Method and apparatus for monitoring the rotating frequency of de-energized induction motors

    DOEpatents

    Mikesell, H.E.; Lucy, E.

    1998-02-03

    The rotational speed of a coasting induction motor is measured by sensing e residual electrical voltages at the power terminals of the motor, thus eliminating the need for conventional tachometer equipment, additional mechanical components or modifications to the induction motor itself. The power terminal voltage signal is detected and transformed into a DC voltage proportional to the frequency of the signal. This DC voltage can be input to the control system of a variable frequency motor controller to regulate the output characteristics thereof relative to the speed of the coasting motor. 6 figs.

  4. Method and apparatus for monitoring the rotating frequency of de-energized induction motors

    DOEpatents

    Mikesell, Harvey E.; Lucy, Eric

    1998-01-01

    The rotational speed of a coasting induction motor is measured by sensing e residual electrical voltages at the power terminals of the motor, thus eliminating the need for conventional tachometer equipment, additional mechanical components or modifications to the induction motor itself. The power terminal voltage signal is detected and transformed into a DC voltage proportional to the frequency of the signal. This DC voltage can be input to the control system of a variable frequency motor controller to regulate the output characteristics thereof relative to the speed of the coasting motor.

  5. Converter Lifetime Assessment for Doubly-Fed Induction Generators Considering Derating Control Strategies at Low Rotor Frequencies

    NASA Astrophysics Data System (ADS)

    Morisse, Marcel; Bartschat, Arne; Wenske, Jan; Mertens, Axel

    2016-09-01

    In this paper, various control strategies around the synchronous operating point with the aim to reduce the thermal loading of the rotor-side converter in wind turbines equipped with doubly-fed induction generators are investigated regarding their assets and drawbacks. It is shown that there are various possibilities to prolong the lifetime expectation of the converter regarding its thermal stress by implementing these control strategies. However, every control measure requires a careful design process or a slight adjustment of the system to ensure a positive effect on the overall behaviour of the wind turbine.

  6. Rotor Losses in a Switched Reluctance Motor - Analysis and Reduction Methods

    NASA Astrophysics Data System (ADS)

    Schweighofer, B.; Recheis, M.; Fulmek, P.; Wegleiter, H.

    2013-01-01

    Due to the increasing hybridization and electrification of vehicles, flywheel energy storage devices are an important area of research. In automotive application besides the weight criteria, some additionally constrains, such as size, efficiency and especially cost have to be fulfilled. Therefore typically a compact design, in which the rotor of the needed electrical machine simultaneously acts as storage mass is chosen. Since the machine is running in vacuum and the rotor can dissipate its heat only by means of thermal radiation or through the bearings if conventional bearings are used, the rotor losses play a vital role. In this work the rotor losses of a switched reluctance machine are analyzed in detail and a method to reduce the rotor losses is proposed.

  7. Rotor reference frame models of a multiloop 2-phase motor drive in brushless DC and microstepping modes

    SciTech Connect

    Chen, J.E.

    1995-12-31

    This paper describes non-linear models of a 2-phase permanent magnet synchronous motor drive in brushless DC and microstepping modes. The models account for everything from the main power bus up to and including the mechanical load and velocity feedback loop. In particular, the models include the power electronics for each phase complete with their internal feedback loops. Classical state space averaged power electronics models are transformed to the rotor reference frame along with the usual electromechanical variables. Since SPICE linearizes the rotor reference frame model about shaft velocity, instead of shaft angle, frequency domain methods apply. The frequency domain analysis detects unstable interactions between torque angle and deliberate feedback within the drives. Time domain simulations using stator reference frame models confirm the results. All models are SPICE-compatible but were developed on Cadence`s Analog Workbench.

  8. Bispectrum of stator phase current for fault detection of induction motor.

    PubMed

    Treetrong, Juggrapong; Sinha, Jyoti K; Gu, Fengshu; Ball, Andrew

    2009-07-01

    A number of research studies has shown that faults in a stator or rotor generally show sideband frequencies around the mains frequency (50 Hz) and at higher harmonics in the spectrum of the Motor Current Signature Analysis (MCSA). However in the present experimental studies such observations have not been seen, but any fault either in the stator or the rotor may distort the sinusoidal response of the motor RPM and the mains frequency so the MCSA response may contain a number of harmonics of the motor RPM and the mains frequency. Hence the use of a higher order spectrum (HOS), namely the bispectrum of the MCSA has been proposed here because it relates both amplitude and phase of number of the harmonics in a signal. It has been observed that it not only detects early faults but also indicates the severity of the fault to some extent.

  9. Integrated Cooling System for Induction Motor Traction Drives, CARAT Program Phase Two Final Report

    SciTech Connect

    Konrad, Charles E.

    2002-12-03

    This Program is directed toward improvements in electric vehicle/hybrid electric vehicle traction systems, and in particular, the development of a low cost, highly efficient, compact traction motor-controller system targeted for high volume automotive use. Because of the complex inter-relationships between the motor and the controller, the combination of motor and controller must be considered as a system in the design and evaluation of overall cost and performance. The induction motor is ideally suited for use as a traction motor because of its basic ruggedness, low cost, and high efficiency. As one can see in Figure 1.1, the induction motor traction drive has been continually evolving through a succession of programs spanning the past fifteen years. VPT marketed an induction motor-based traction drive system, the EV2000, which proved to be a reliable, high performance system that was used in a wide range of vehicles. The EV2000 drives evolved from the Modular Electric Vehicle Program (MEVP) and has been used in vehicles ranging in size from 3,000 lb. autos and utility vans, to 32,000 lb. city transit buses. Vehicles powered by the EV2000 induction motor powertrain have accumulated over 2 million miles of service. The EV2000 induction motor system represents 1993 state-of-the-art technology, and evolved from earlier induction motor programs that drove induction motor speeds up to 15,000 rpm to reduce the motor size and cost. It was recognized that the improvements in power density and motor cost sought in the PNGV program could only be achieved through increases in motor speed. Esson’s Rule for motor power clearly states that the power obtainable from a given motor design is the product of motor speed and volume. In order to meet the CARAT Program objectives, the maximum speed goal of the induction motor designed in this Program was increased from 15,000 rpm to 20,000 rpm while maintaining the efficiency and durability demonstrated by lower speed designs done in

  10. Aerospace induction motor actuators driven from a 20-kHz power link

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Aerospace electromechanical actuators utilizing induction motors are under development in sizes up to 40 kW. While these actuators have immediate application to the Advanced Launch System (ALS) program, several potential applications are currently under study including the Advanced Aircraft Program. Several recent advances developed for the Space Station Freedom have allowed induction motors to be selected as a first choice for such applications. Among these technologies are bi-directional electronics and high frequency power distribution techniques. Each of these technologies are discussed with emphasis on their impact upon induction motor operation.

  11. Energy-saving technology of vector controlled induction motor based on the adaptive neuro-controller

    NASA Astrophysics Data System (ADS)

    Engel, E.; Kovalev, I. V.; Karandeev, D.

    2015-10-01

    The ongoing evolution of the power system towards a Smart Grid implies an important role of intelligent technologies, but poses strict requirements on their control schemes to preserve stability and controllability. This paper presents the adaptive neuro-controller for the vector control of induction motor within Smart Gird. The validity and effectiveness of the proposed energy-saving technology of vector controlled induction motor based on adaptive neuro-controller are verified by simulation results at different operating conditions over a wide speed range of induction motor.

  12. Passive magnetic bearing for a motor-generator

    DOEpatents

    Post, Richard F.

    2006-07-18

    Conductive lap windings are interleaved with conventional loops in the stator of a motor-generator. The rotor provides magnetic induction lines that, when rotated, cut across the lap windings and the loops. When the rotor is laterally displaced from its equilibrium axis of rotation, its magnetic lines of induction induce a current in the interleaved lap windings. The induced current interacts with the magnetic lines of induction of the rotor in accordance with Lenz's law to generate a radial force that returns the rotor to its equilibrium axis of rotation.

  13. 22. DIABLO POWERHOUSE: COOLING WATER PUMPS (WESTINGHOUSE C.S. INDUCTION MOTORS), ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. DIABLO POWERHOUSE: COOLING WATER PUMPS (WESTINGHOUSE C.S. INDUCTION MOTORS), 1989. - Skagit Power Development, Diablo Powerhouse, On Skagit River, 6.1 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  14. Multilevel DC Link Inverter for Brushless Permanent Magnet Motors with Very Low Inductance

    SciTech Connect

    Su, G.J.

    2001-10-29

    Due to their long effective air gaps, permanent magnet motors tend to have low inductance. The use of ironless stator structure in present high power PM motors (several tens of kWs) reduces the inductance even further (< 100 {micro}H). This low inductance imposes stringent current regulation demands for the inverter to obtain acceptable current ripple. An analysis of the current ripple for these low inductance brushless PM motors shows that a standard inverter with the most commonly used IGBT switching devices cannot meet the current regulation demands and will produce unacceptable current ripples due to the IGBT's limited switching frequency. This paper introduces a new multilevel dc link inverter, which can dramatically reduce the current ripple for brushless PM motor drives. The operating principle and design guidelines are included.

  15. Optimal efficiency vector control of induction motor drive system for drum washing machine

    NASA Astrophysics Data System (ADS)

    Lee, Won Cheol; Yu, Jae Sung; Jang, Bong An; Won, Chung Yuen

    2005-12-01

    In home appliances, electric energy is optimally controlled by using power electronics technology, creating a comfortable environment in terms of energy saving, low sound generation, and reduced time consumption. Usually simplicity and robustness make the three phase induction motor attractive for use in domestic appliance, including washing machines. Two main types of domestic washing machine have evolved. We focus on efficiency of the front loading machine favored in Europe, which has a horizontal drum axis. This paper presents the control algorithm for optimal efficiency drives of an induction motor for drum washing machine. This system uses a simple model of the induction motor that include equations of the iron losses. The proposed optimal efficiency control algorithm calculates commands of the reference torque and flux currents for the flux oriented control of the induction motor. The proposed algorithm is verified through digital simulation.

  16. Use of fuzzy inference system for condition monitoring of induction motor

    NASA Astrophysics Data System (ADS)

    Janier, Josefina B.; Zaim Zaharia, M. F.; Karim, Samsul Ariffin Abd.

    2012-09-01

    Three phase induction motors are commonly used in industry due to its robustness, simplicity of its construction and high reliability. The tasks performed by these motors grow increasingly complex because of modern industries hence there is a need to determine the faults. Early detection of faults will reduce an unscheduled machine downtime that can upset production deadlines and may cause heavy financial losses. This paper is focused in developing a computer based system using Fuzzy Inference system's membership function. An unusual increase in vibration of the motor could be an indicator of faulty condition hence the vibration of the motor of an induction motor was used as an input, whereas the output is the motor condition. An inference system of the Fuzzy Logic was created to classify the vibration characteristics of the motor which is called vibration analysis. The system classified the motor of the gas distribution pump condition as from 'acceptable' to 'monitor closely'. The early detection of unusual increase in vibration of the induction motor is an important part of a predictive maintenance for motor driven machinery.

  17. 29. INDUCTION MOTOR (6600 VOLTS, 5750 H.P.) DRIVES THE 21INCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. INDUCTION MOTOR (6600 VOLTS, 5750 H.P.) DRIVES THE 21-INCH AND 18-INCH BILLET MILLS. MOTOR WAS MANUFACTURED BY THE GENERAL ELECTRIC COMPANY, SCHENECTADY, NEW YORK. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

  18. Efficiency testing of medium induction motors: A comment on IEEE Std 112-1991

    SciTech Connect

    Gray, G.G.; Martiny, W.J.

    1996-09-01

    The energy crisis of 1973 focused attention on the efficiency of polyphase induction motors, and the need to have a test procedure that was repeatable and accurate. Medium induction motors, especially those in the size range 1 through 125 horsepower, were important because of the large number in service and the fact that a significant efficiency improvement through redesign was economically feasible. In response to this the ANSI/IEEE Std. 112, ``IEEE Standard Test Procedure for Polyphase Induction Motors and Generators`` Method B was chosen for testing medium ac motors for efficiency. The current version IEEE std. 112-1991 Method B contains several requirements for accuracy improvement which have been found to be effective. Even though the Method B procedure with the additional accuracy requirement has been in use since 1984 no rational has been published to support these extra requirements. The paper discusses the purpose of these improvements, and also point out some weakness in procedure.

  19. EFFICIENCY OPTIMIZATIN CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS

    EPA Science Inventory

    The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. This energy optimizer is complemented by a sensorless speed controller that maintains motor shaft re...

  20. Comparison of induction motor field efficiency evaluation methods

    SciTech Connect

    Hsu, J.S.; Kueck, J.D.; Olszewski, M.; Casada, D.A.; Otaduy, P.J.; Tolbert, L.M.

    1996-10-01

    Unlike testing motor efficiency in a laboratory, certain methods given in the IEEE-Std 112 cannot be used for motor efficiency in the field. For example, it is difficult to load a motor in the field with a dynamometer when the motor is already coupled to driven equipment. The motor efficiency field evaluation faces a different environment from that for which the IEEE-Std 112 is chiefly written. A field evaluation method consists of one or several basic methods according to their physical natures. Their intrusivenesses and accuracies are also discussed. This study is useful for field engineers to select or to establish a proper efficiency evaluation method by understanding the theories and error sources of the methods.

  1. Numerical calculation of primary slot leakage inductance of a Single-sided HTS linear induction motor used for linear metro

    NASA Astrophysics Data System (ADS)

    Li, Dong; Wen, Yinghong; Li, Weili; Fang, Jin; Cao, Junci; Zhang, Xiaochen; Lv, Gang

    2017-03-01

    In the paper, the numerical method calculating asymmetric primary slot leakage inductances of Single-sided High-Temperature Superconducting (HTS) Linear Induction Motor (HTS LIM) is presented. The mathematical and geometric models of three-dimensional nonlinear transient electromagnetic field are established and the boundary conditions are also given. The established model is solved by time-stepping Finite Element Method (FEM). Then, the three-phase asymmetric primary slot leakage inductances under different operation conditions are calculated by using the obtained electromagnetic field distribution. The influences of the special effects such as longitudinal end effects, transversal edge effects, etc. on the primary slot leakage inductance are investigated. The presented numerical method is validated by experiments carried out on a 3.5 kW prototype with copper wires which has the same structures with the HTS LIM.

  2. Methods of torque ripple reduction for flux reversal motor

    NASA Astrophysics Data System (ADS)

    Vakil, Gaurang; Sheth, N. K.; Miller, David

    2009-04-01

    This paper presents two-dimensional finite element based results for various methods of torque ripple reduction in flux-reversal motors. The effects of variation in magnet and rotor pole heights, rotor pole skewing, and multiple teeth per rotor pole on the cogging torque, developed torque, torque ripple, and phase inductance and also an optimum value of the magnet and rotor pole heights, skew angle, and choice of teeth per rotor pole with the teeth depth resulting in torque ripple reduction are presented.

  3. Dual rotor single- stator axial air gap PMSM motor/generator drive for high torque vehicles applications

    NASA Astrophysics Data System (ADS)

    Tutelea, L. N.; Deaconu, S. I.; Boldea, I.; Popa, G. N.

    2014-03-01

    The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper.

  4. Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Lorenz, Robert D.

    2001-01-01

    A new, deadbeat type of direct torque control is proposed, analyzed, and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.

  5. Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Lorenz, Robert D.

    2003-01-01

    A new, deadbeat type of direct torque control is proposed, analyzed and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.

  6. Stator and Rotor Flux Based Deadbeat Direct Torque Control of Induction Machines. Revision 1

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Lorenz, Robert D.

    2002-01-01

    A new, deadbeat type of direct torque control is proposed, analyzed, and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows a graphical representation which is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position and speed sensorless implementation of the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low speed operation. The paper first develops the new, deadbeat DTC methodology and graphical representation of the new algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods.

  7. Instantaneous stator power as a medium for the signature analysis of induction motors

    SciTech Connect

    Legowski, S.F.; Ula, A.H.M.S.; Trzynadlowski, A.M.

    1995-12-31

    Preventive maintenance of electric drive systems with induction motors involves continuous monitoring of operation, to detect electrical and mechanical conditions that may lead to a failure. Intensive research effort has been for some time focused on the motor current signature analysis (MCSA). The MCSA techniques utilize results of spectral analysis of the stator current of an induction motor to diagnose abnormal conditions both in the motor and driven system. Reliable interpretation of the current spectra is difficult, as distortions of the current waveform caused by abnormalities in the drive system are usually minute. In this paper, an alternate medium for the motor signature analysis, namely the instantaneous stator power, is proposed. It is shown, both by computer simulations and laboratory experiments, that the instantaneous power carries more information than the current itself, since not only the current magnitude but also the phase shift between the current and voltage waveforms are affected by the irregularities in the motor or other parts of the drive system. Utilization of the instantaneous stator power as a medium for the signature analysis opens new possibilities in the automated diagnostics of induction motor drives.

  8. Polygonal shaft hole rotor

    DOEpatents

    Hussey, John H.; Rose, John Scott; Meystrik, Jeffrey J.; White, Kent Lee

    2001-01-23

    A laminated rotor for an induction motor has a plurality of ferro-magnetic laminations mounted axially on a rotor shaft. Each of the plurality of laminations has a central aperture in the shape of a polygon with sides of equal length. The laminations are alternatingly rotated 180.degree. from one another so that the straight sides of the polygon shaped apertures are misaligned. As a circular rotor shaft is press fit into a stack of laminations, the point of maximum interference occurs at the midpoints of the sides of the polygon (i.e., at the smallest radius of the central apertures of the laminations). Because the laminates are alternatingly rotated, the laminate material at the points of maximum interference yields relatively easily into the vertices (i.e., the greatest radius of the central aperture) of the polygonal central aperture of the next lamination as the shaft is inserted into the stack of laminations. Because of this yielding process, the amount of force required to insert the shaft is reduced, and a tighter fit is achieved.

  9. Evaluation of half wave induction motor drive for use in passenger vehicles

    NASA Technical Reports Server (NTRS)

    Hoft, R. G.; Kawamura, A.; Goodarzi, A.; Yang, G. Q.; Erickson, C. L.

    1985-01-01

    Research performed at the University of Missouri-Columbia to devise and design a lower cost inverter induction motor drive for electrical propulsion of passenger vehicles is described. A two phase inverter motor system is recommended. The new design is predicted to provide comparable vehicle performance, improved reliability and a cost advantage for a high production vehicle, decreased total rating of the power semiconductor switches, and a somewhat simpler control hardware compared to the conventional three phase bridge inverter motor drive system. The major disadvantages of the two phase inverter motor drive are that it is larger and more expensive than a three phase machine, the design of snubbers for the power leakage inductances produce higher transient voltages, and the torque pulsations are relatively large because of the necessity to limit the inverter switching frequency to achieve high efficiency.

  10. Chaos Suppression in Fractional Order Permanent Magnet Synchronous Motor and PI controlled Induction motor by Extended Back stepping Control

    NASA Astrophysics Data System (ADS)

    Rajagopal, Karthikeyan; Karthikeyan, Anitha; Duraisamy, Prakash

    2016-12-01

    In this paper we investigate the control of three-dimensional non-autonomous fractional-order model of a permanent magnet synchronous motor (PMSM) and PI controlled fractional order Induction motor via recursive extended back stepping control technique. A robust generalized weighted controllers are derived to suppress the chaotic oscillations of the fractional order model. As the direct Lyapunov stability analysis of the controller is difficult for a fractional order first derivative, we have derived a new lemma to analyze the stability of the system. Numerical simulations of the proposed chaos suppression methodology are given to prove the analytical results.

  11. Neural-network-based speed controller for induction motors using inverse dynamics model

    NASA Astrophysics Data System (ADS)

    Ahmed, Hassanein S.; Mohamed, Kamel

    2016-08-01

    Artificial Neural Networks (ANNs) are excellent tools for controller design. ANNs have many advantages compared to traditional control methods. These advantages include simple architecture, training and generalization and distortion insensitivity to nonlinear approximations and nonexact input data. Induction motors have many excellent features, such as simple and rugged construction, high reliability, high robustness, low cost, minimum maintenance, high efficiency, and good self-starting capabilities. In this paper, we propose a neural-network-based inverse model for speed controllers for induction motors. Simulation results show that the ANNs have a high tracing capability.

  12. Variable-Speed Induction Motor Drives for Aircraft Environmental Control Compressors

    NASA Technical Reports Server (NTRS)

    Mildice, J. W.; Hansen, I. G.; Schreiner, K. E.; Roth, M. E.

    1996-01-01

    New, more-efficient designs for aircraft jet engines are not capable of supplying the large quantities of bleed air necessary to provide pressurization and air conditioning for the environmental control systems (ECS) of the next generation of large passenger aircraft. System analysis and engineering have determined that electrically-driven ECS can help to maintain the improved fuel efficiencies; and electronic controllers and induction motors are now being developed in a NASA/NPD SBIR Program to drive both types of ECS compressors. Previous variable-speed induction motor/controller system developments and publications have primarily focused on field-oriented control, with large transient reserve power, for maximum acceleration and optimum response in actuator and robotics systems. The application area addressed herein is characterized by slowly-changing inputs and outputs, small reserve power capability for acceleration, and optimization for maximum efficiency. This paper therefore focuses on the differences between this case and the optimum response case, and shows the development of this new motor/controller approach. It starts with the creation of a new set of controller requirements. In response to those requirements, new control algorithms are being developed and implemented in an embedded computer, which is integrated into the motor controller closed loop. Buffered logic outputs are used to drive the power switches in a resonant-technology, power processor/motor-controller, at switching/resonant frequencies high enough to support efficient high-frequency induction motor operation at speeds up to 50,000-RPA

  13. Dual-circuit segmented rail phased induction motor

    DOEpatents

    Marder, Barry M.; Cowan, Jr., Maynard

    2002-01-01

    An improved linear motor utilizes two circuits, rather that one circuit and an opposed plate, to gain efficiency. The powered circuit is a flat conductive coil. The opposed segmented rail circuit is either a plurality of similar conductive coils that are shorted, or a plurality of ladders formed of opposed conductive bars connected by a plurality of spaced conductors. In each embodiment, the conductors are preferably cables formed from a plurality of intertwined insulated wires to carry current evenly.

  14. Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

    NASA Astrophysics Data System (ADS)

    Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman

    2016-02-01

    Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.

  15. Smart Sensor for Online Detection of Multiple-Combined Faults in VSD-Fed Induction Motors

    PubMed Central

    Garcia-Ramirez, Armando G.; Osornio-Rios, Roque A.; Granados-Lieberman, David; Garcia-Perez, Arturo; Romero-Troncoso, Rene J.

    2012-01-01

    Induction motors fed through variable speed drives (VSD) are widely used in different industrial processes. Nowadays, the industry demands the integration of smart sensors to improve the fault detection in order to reduce cost, maintenance and power consumption. Induction motors can develop one or more faults at the same time that can be produce severe damages. The combined fault identification in induction motors is a demanding task, but it has been rarely considered in spite of being a common situation, because it is difficult to identify two or more faults simultaneously. This work presents a smart sensor for online detection of simple and multiple-combined faults in induction motors fed through a VSD in a wide frequency range covering low frequencies from 3 Hz and high frequencies up to 60 Hz based on a primary sensor being a commercially available current clamp or a hall-effect sensor. The proposed smart sensor implements a methodology based on the fast Fourier transform (FFT), RMS calculation and artificial neural networks (ANN), which are processed online using digital hardware signal processing based on field programmable gate array (FPGA).

  16. Measurement in a wind tunnel of the modification of mean wind and turbulence characteristics due to induction effects near wind turbine rotors

    SciTech Connect

    Neff, D.E.; Meroney, R.N.

    1987-08-01

    It is the purpose of this report to provide experimental data on the wind field surrounding a single model wind turbine rotor disk. These data should provide an improved physical insight into the induction effects of the air flow as it approaches the wind turbine. This insight should in turn improve an analytical model's predictive capabilities. A scaled model of a horizontal-axis wind turbine (a two-bladed rotor of diameter 53 cm) was placed into the Meteorological Wind Tunnel (MWT) facility at Colorado State University (cross-section width of 183 cm). Four different approach flow conditions were studied: low and moderate turbulence levels (0.1% and 1.5% intensity) at both 6 and 7.6 m/s freestream air velocities. For each of these flow conditions the rotor power coefficient versus tip speed ratio was obtained, and the 3-dimensional velocity field from 3 rotor diameters upwind to 0.5 diameter downwind was tabulated. The power output of the rotor was obtained via a simple prony brake friction device that imparts a torque (measured by the deflection of a spring) to the spinning shaft of the wind turbine. The rotor speed, measured by a strobe light, was observed to vary with load from 900 rpm up to 2100 rpm for the flow conditions described above. The 3-dimensional velocity field was measured via a three-hot-film probe. Details of the measurement techniques are provided. The test program and data results are also given. A short discussion of the implications of this data set is included. 12 refs., 19 figs., 11 tabs.

  17. Detection of Broken Rotor Bars in Induction Motors Using Stator Current Measurements

    DTIC Science & Technology

    1988-05-01

    Certified by: 4 C Paul E. Sullivan, Thesis Reader Associate Professor of Naval Architecture Accepted by: A. Douglas Carmichael, Chairman Ocean Engineering... Lbl ... LbrN fB [L]= (2-55) L , s a L , . f a b L , ? N ot e L , . , , . .. L ’, , , N , 4 o fi’a ib [I] ’ lri (2-56) * irNRB The flux linkages are...Fitzgerald, C. Kingsley, Jr., and S. D. Umans, Electric Machinery. New York, NY: McGraw-Hill, 1983 . 13. M. L. James, G. M. Smith, and J. C. Wolford, Applied

  18. Modeling and Simulating of Single Side Short Stator Linear Induction Motor with the End Effect

    NASA Astrophysics Data System (ADS)

    Hamzehbahmani, Hamed

    2011-09-01

    Linear induction motors are under development for a variety of demanding applications including high speed ground transportation and specific industrial applications. These applications require machines that can produce large forces, operate at high speeds, and can be controlled precisely to meet performance requirements. The design and implementation of these systems require fast and accurate techniques for performing system simulation and control system design. In this paper, a mathematical model for a single side short stator linear induction motor with a consideration of the end effects is presented; and to study the dynamic performance of this linear motor, MATLAB/SIMULINK based simulations are carried out, and finally, the experimental results are compared to simulation results.

  19. The torque ripple reduction of a concentrated winding synchronous reluctance motor according to stator and rotor structure variations using response surface methodology

    NASA Astrophysics Data System (ADS)

    Choi, Yun-Chul; Lee, Jung-Ho; Hong, Jung Pyo

    2008-04-01

    This paper deals with optimum design criteria to minimize the torque ripple of a concentrated winding synchronous reluctance motor (SynRM) using response surface methodology (RSM). The feasibility of using RSM with the finite element method in practical engineering problem is investigated with computational examples and comparison between the fitted response and the results obtained from an analytical solution according to the design variables of stator and rotor in concentrated winding SynRM (6slot).

  20. Sensor and sensorless fault tolerant control for induction motors using a wavelet index.

    PubMed

    Gaeid, Khalaf Salloum; Ping, Hew Wooi; Khalid, Mustafa; Masaoud, Ammar

    2012-01-01

    Fault Tolerant Control (FTC) systems are crucial in industry to ensure safe and reliable operation, especially of motor drives. This paper proposes the use of multiple controllers for a FTC system of an induction motor drive, selected based on a switching mechanism. The system switches between sensor vector control, sensorless vector control, closed-loop voltage by frequency (V/f) control and open loop V/f control. Vector control offers high performance, while V/f is a simple, low cost strategy with high speed and satisfactory performance. The faults dealt with are speed sensor failures, stator winding open circuits, shorts and minimum voltage faults. In the event of compound faults, a protection unit halts motor operation. The faults are detected using a wavelet index. For the sensorless vector control, a novel Boosted Model Reference Adaptive System (BMRAS) to estimate the motor speed is presented, which reduces tuning time. Both simulation results and experimental results with an induction motor drive show the scheme to be a fast and effective one for fault detection, while the control methods transition smoothly and ensure the effectiveness of the FTC system. The system is also shown to be flexible, reverting rapidly back to the dominant controller if the motor returns to a healthy state.

  1. Sensor and Sensorless Fault Tolerant Control for Induction Motors Using a Wavelet Index

    PubMed Central

    Gaeid, Khalaf Salloum; Ping, Hew Wooi; Khalid, Mustafa; Masaoud, Ammar

    2012-01-01

    Fault Tolerant Control (FTC) systems are crucial in industry to ensure safe and reliable operation, especially of motor drives. This paper proposes the use of multiple controllers for a FTC system of an induction motor drive, selected based on a switching mechanism. The system switches between sensor vector control, sensorless vector control, closed-loop voltage by frequency (V/f) control and open loop V/f control. Vector control offers high performance, while V/f is a simple, low cost strategy with high speed and satisfactory performance. The faults dealt with are speed sensor failures, stator winding open circuits, shorts and minimum voltage faults. In the event of compound faults, a protection unit halts motor operation. The faults are detected using a wavelet index. For the sensorless vector control, a novel Boosted Model Reference Adaptive System (BMRAS) to estimate the motor speed is presented, which reduces tuning time. Both simulation results and experimental results with an induction motor drive show the scheme to be a fast and effective one for fault detection, while the control methods transition smoothly and ensure the effectiveness of the FTC system. The system is also shown to be flexible, reverting rapidly back to the dominant controller if the motor returns to a healthy state. PMID:22666016

  2. Control algorithm for the inverter fed induction motor drive with DC current feedback loop based on principles of the vector control

    SciTech Connect

    Vuckovic, V.; Vukosavic, S. )

    1992-01-01

    This paper brings out a control algorithm for VSI fed induction motor drives based on the converter DC link current feedback. It is shown that the speed and flux can be controlled over the wide speed and load range quite satisfactorily for simpler drives. The base commands of both the inverter voltage and frequency are proportional to the reference speed, but each of them is further modified by the signals derived from the DC current sensor. The algorithm is based on the equations well known from the vector control theory, and is aimed to obtain the constant rotor flux and proportionality between the electrical torque, the slip frequency and the active component of the stator current. In this way, the problems of slip compensation, Ri compensation and correction of U/f characteristics are solved in the same time. Analytical considerations and computer simulations of the proposed control structure are in close agreement with the experimental results measured on a prototype drive.

  3. Halbach Magnetic Rotor Development

    NASA Technical Reports Server (NTRS)

    Gallo, Christopher A.

    2008-01-01

    The NASA John H. Glenn Research Center has a wealth of experience in Halbach array technology through the Fundamental Aeronautics Program. The goals of the program include improving aircraft efficiency, reliability, and safety. The concept of a Halbach magnetically levitated electric aircraft motor will help reduce harmful emissions, reduce the Nation s dependence on fossil fuels, increase efficiency and reliability, reduce maintenance and decrease operating noise levels. Experimental hardware systems were developed in the GRC Engineering Development Division to validate the basic principles described herein and the theoretical work that was performed. A number of Halbach Magnetic rotors have been developed and tested under this program. A separate test hardware setup was developed to characterize each of the rotors. A second hardware setup was developed to test the levitation characteristics of the rotors. Each system focused around a unique Halbach array rotor. Each rotor required original design and fabrication techniques. A 4 in. diameter rotor was developed to test the radial levitation effects for use as a magnetic bearing. To show scalability from the 4 in. rotor, a 1 in. rotor was developed to also test radial levitation effects. The next rotor to be developed was 20 in. in diameter again to show scalability from the 4 in. rotor. An axial rotor was developed to determine the force that could be generated to position the rotor axially while it is rotating. With both radial and axial magnetic bearings, the rotor would be completely suspended magnetically. The purpose of this report is to document the development of a series of Halbach magnetic rotors to be used in testing. The design, fabrication and assembly of the rotors will be discussed as well as the hardware developed to test the rotors.

  4. Evaluation of induction motor performance using an electronic power factor controller

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The concept of reducing the losses in an induction motor by electronically controlling the time interval between the zero crossing of the applied voltage and the zero crossing of the armature current was evaluated. The effect on power losses and power factor of reducing the applied sinusoidal voltages below the rated value was investigated experimentally. The reduction in power losses was measured using an electronic controller designed and built at MSFC. Modifications to the MSFC controller are described as well as a manually controlled electronic device which does not require that the motor be wye connected and the neutral available. Possible energy savings are examined.

  5. Flywheel induction motor-generator for magnet power supply in small fusion device.

    PubMed

    Hatakeyma, S; Yoshino, F; Tsutsui, H; Tsuji-Iio, S

    2016-04-01

    A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms).

  6. Flywheel induction motor-generator for magnet power supply in small fusion device

    NASA Astrophysics Data System (ADS)

    Hatakeyma, S.; Yoshino, F.; Tsutsui, H.; Tsuji-Iio, S.

    2016-04-01

    A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms).

  7. Rotor dynamic behaviour of a high-speed oil-free motor compressor with a rigid coupling supported on four radial magnetic bearings

    NASA Technical Reports Server (NTRS)

    Schmied, J.; Pradetto, J. C.

    1994-01-01

    The combination of a high-speed motor, dry gas seals, and magnetic bearings realized in this unit facilitates the elimination of oil. The motor is coupled with a quill shaft to the compressor. This yields higher natural frequencies of the rotor than with the use of a diaphragm coupling and helps to maintain a sufficient margin of the maximum speed to the frequency of the second compressor bending mode. However, the controller of each bearing then has to take the combined modes of both machines into account. The requirements for the controller to ensure stability and sufficient damping of all critical speeds are designed and compared with the implemented controller. The calculated closed loop behavior was confirmed experimentally, except the stability of some higher modes due to slight frequency deviations of the rotor model to the actual rotor. The influence of a mechanical damper as a device to provide additional damping to high models is demonstrated theoretically. After all, it was not necessary to install the damper, since all modes cold be stabilized by the controller.

  8. A combined lift and propulsion system of a steel plate by transverse flux linear induction motors

    SciTech Connect

    Hayashiya, H.; Ohsaki, H.; Masada, E.

    1999-09-01

    To realize a non-contacting conveyance of a steel plate, a combined lift and propulsion system of a steel plate by transverse flux linear induction motors (LIMs) is proposed. By introducing the DC biased AC feeding to the LIM< a steel plate is supported stably and efficiently. In this paper, after showing the advantages of the system, the magnetic levitation experiments are carried out to investigate the feasibility of the system.

  9. Misalignment detection in induction motors with flexible coupling by means of estimated torque analysis and MCSA

    NASA Astrophysics Data System (ADS)

    Verucchi, Carlos; Bossio, José; Bossio, Guillermo; Acosta, Gerardo

    2016-12-01

    In recent years, progress has been made in developing techniques to detect mechanical faults in actuators driven by induction motors. The latest developments show their capability to detect faults from the analysis of the motor electrical variables. The techniques are based on the analysis of the Motor Current Signature Analysis (MCSA) and the Load Torque Signature Analysis (LTSA), among others. Thus, failures such as misalignment between the motor and load, progressive gear teeth wear, and mass imbalances have been successfully detected. In case of misalignment between the motor and load, both angular and radial misalignment, the results presented in literature do not consider the characteristics of the coupling device. In this work, it is studied a mechanism in which the power transmission between the motor and load is performed by means of different types of couplings, mainly those most frequently used in industry. Results show that the conclusions drawn for a particular coupling are not necessarily applicable to others. Finally, this paper presents data of interest for the development of algorithms or expert systems for fault detection and diagnosis.

  10. A New High Speed Induction Motor Drive based on Field Orientation and Hysteresis Current Comparison

    NASA Astrophysics Data System (ADS)

    Ogbuka, Cosmas; Nwosu, Cajethan; Agu, Marcel

    2016-09-01

    This paper presents a new high speed induction motor drive based on the core advantage of field orientation control (FOC) and hysteresis current comparison (HCC). A complete closed loop speed-controlled induction motor drive system is developed consisting of an outer speed and an inner HCC algorithm which are optimised to obtain fast and stable speed response with effective current and torque tracking, both during transient and steady states. The developed model, being speed-controlled, was examined with step and ramp speed references and excellent performances obtained under full load stress. A speed response comparison of the model with the standard AC3 (Field-Oriented Control Induction Motor Drive) of MATLAB Simpower systems shows that the model achieved a rise time of 0.0762 seconds compared to 0.2930 seconds achieved by the AC3. Also, a settle time of 0.0775 seconds was obtained with the developed model while that of the AC3 model is 0.2986 seconds confirming, therefore, the superiority of the developed model over the AC3 model which, hitherto, served as a reference standard.

  11. Novel Observer Scheme of Fuzzy-MRAS Sensorless Speed Control of Induction Motor Drive

    NASA Astrophysics Data System (ADS)

    Chekroun, S.; Zerikat, M.; Mechernene, A.; Benharir, N.

    2017-01-01

    This paper presents a novel approach Fuzzy-MRAS conception for robust accurate tracking of induction motor drive operating in a high-performance drives environment. Of the different methods for sensorless control of induction motor drive the model reference adaptive system (MRAS) finds lot of attention due to its good performance. The analysis of the sensorless vector control system using MRAS is presented and the resistance parameters variations and speed observer using new Fuzzy Self-Tuning adaptive IP Controller is proposed. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The present approach helps to achieve a good dynamic response, disturbance rejection and low to plant parameter variations of the induction motor. In order to verify the performances of the proposed observer and control algorithms and to test behaviour of the controlled system, numerical simulation is achieved. Simulation results are presented and discussed to shown the validity and the performance of the proposed observer.

  12. Application to induction motor faults diagnosis of the amplitude recovery method combined with FFT

    NASA Astrophysics Data System (ADS)

    Liu, Yukun; Guo, Liwei; Wang, Qixiang; An, Guoqing; Guo, Ming; Lian, Hao

    2010-11-01

    This paper presents a signal processing method - amplitude recovery method (abbreviated to ARM) - that can be used as the signal pre-processing for fast Fourier transform (FFT) in order to analyze the spectrum of the other-order harmonics rather than the fundamental frequency in stator currents and diagnose subtle faults in induction motors. In this situation, the ARM functions as a filter that can filter out the component of the fundamental frequency from three phases of stator currents of the induction motor. The filtering result of the ARM can be provided to FFT to do further spectrum analysis. In this way, the amplitudes of other-order frequencies can be extracted and analyzed independently. If the FFT is used without the ARM pre-processing and the components of other-order frequencies, compared to the fundamental frequency, are fainter, the amplitudes of other-order frequencies are not able easily to extract out from stator currents. The reason is when the FFT is used direct to analyze the original signal, all the frequencies in the spectrum analysis of original stator current signal have the same weight. The ARM is capable of separating the other-order part in stator currents from the fundamental-order part. Compared to the existent digital filters, the ARM has the benefits, including its stop-band narrow enough just to stop the fundamental frequency, its simple operations of algebra and trigonometry without any integration, and its deduction direct from mathematics equations without any artificial adjustment. The ARM can be also used by itself as a coarse-grained diagnosis of faults in induction motors when they are working. These features can be applied to monitor and diagnose the subtle faults in induction motors to guard them from some damages when they are in operation. The diagnosis application of ARM combined with FFT is also displayed in this paper with the experimented induction motor. The test results verify the rationality and feasibility of the

  13. Improvement of the Analytical Model of a Laminated Core Parametric Motor

    NASA Astrophysics Data System (ADS)

    Tajima, Katsubumi; Sato, Tadashi; Sakamoto, Yoshinori

    A laminated core parametric induction motor has desirable features and the planer structure to make it possible to reduce the production cost of the motor by mass production. In the past work, we showed the validity to apply the two-dimensional reluctance network analytical model to the dynamic analysis of the motor while the rotor is driving. In this paper, we investigate the improvement the accuracy of the analytical method of the motor by using new reluctance network analytical model of the motor. In this model, the magnetic circuits of the stator and the rotor are connected by the variable reluctances that are expressed as the function of the rotating angle.

  14. Method and apparatus for pulse width modulation control of an AC induction motor

    NASA Technical Reports Server (NTRS)

    Geppert, Steven (Inventor); Slicker, James M. (Inventor)

    1984-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

  15. Method and apparatus for pulse width modulation control of an AC induction motor

    DOEpatents

    Geppert, Steven; Slicker, James M.

    1984-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  16. Universal Parameter Measurement and Sensorless Vector Control of Induction and Permanent Magnet Synchronous Motors

    NASA Astrophysics Data System (ADS)

    Yamamoto, Shu; Ara, Takahiro

    Recently, induction motors (IMs) and permanent-magnet synchronous motors (PMSMs) have been used in various industrial drive systems. The features of the hardware device used for controlling the adjustable-speed drive in these motors are almost identical. Despite this, different techniques are generally used for parameter measurement and speed-sensorless control of these motors. If the same technique can be used for parameter measurement and sensorless control, a highly versatile adjustable-speed-drive system can be realized. In this paper, the authors describe a new universal sensorless control technique for both IMs and PMSMs (including salient pole and nonsalient pole machines). A mathematical model applicable for IMs and PMSMs is discussed. Using this model, the authors derive the proposed universal sensorless vector control algorithm on the basis of estimation of the stator flux linkage vector. All the electrical motor parameters are determined by a unified test procedure. The proposed method is implemented on three test machines. The actual driving test results demonstrate the validity of the proposed method.

  17. The pulsed linear induction motor concept for high-speed trains

    SciTech Connect

    Turman, B.N.; Marder, B.M.; Rohwein, G.J.; Aeschliman, D.P.; Kelley, J.B.; Cowan, M.; Zimmerman, R.M.

    1995-06-01

    The SERAPBIM (SEgmented RAil PHased Induction Motor) concept is a linear induction motor concept which uses rapidly-pulsed magnetic fields and a segmented reaction rail, as opposed to low-frequency fields and continuous reaction rails found in conventional linear induction motors. These improvements give a high-traction, compact, and efficient linear motor that has potential for advanced high speed rail propulsion. In the SERAPBIM concept, coils on the vehicle push against a segmented aluminum rail, which is mounted on the road bed. Current is pulsed as the coils cross an edge of the segmented rail, inducing surface currents which repel the coil. The coils must be pulsed in synchronization with the movement by reaction rail segments. This is provided by a sense-and-fire circuit that controls the pulsing of the power modulators. Experiments were conducted to demonstrate the feasibility of the pulsed induction motor and to collect data that could be used for scaling calculations. A 14.4 kg aluminum plate was accelerated down a 4 m track to speeds of over 15 m/sec with peak thrust up to 18 kN per coilset. For a trainset capable of 200 mph speed, the SERAPHIM concept design is based on coils which are each capable of producing up to 3.5 kN thrust, and 30 coil pairs are mounted on each power car. Two power cars, one at each end of the train, provide 6 MW from two gas turbine prime power units. The thrust is about 210.000 N and is essentially constant up to 200 km/hr since wheel slippage does not limit thrust as with conventional wheeled propulsion. A key component of the SERAPHIM concept is the use of passive wheel-on-rah support for the high speed vehicle. Standard steel wheels are capable of handling over 200 mph. The SERAPHIM cost is comparable to that for steel-wheel high-speed rail, and about 10% to 25% of the projected costs for a comparable Maglev system.

  18. A high temperature superconducting induction/synchronous motor with a ten-fold improvement in torque density

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Matsumura, K.; Nishimura, T.; Nagao, K.; Yamada, Y.; Amemiya, N.; Itoh, Y.; Terazawa, T.; Osamura, K.

    2011-01-01

    In this paper, the enhancement of the torque density in a high temperature superconductor (HTS) induction/synchronous machine is experimentally and theoretically investigated by the use of Bi-2223 windings. The basic structure of this machine is the same as that of a conventional squirrel-cage induction motor, and the secondary windings are replaced by the superconducting tapes. Firstly, quantitative values of the enhanced torque are measured in an experiment using a fabricated motor at 77 K. Then, such a torque result is theoretically confirmed based upon the analytical expression, which is derived from the nonlinear electrical equivalent circuit. It is shown that the theoretical and experimental results agree well with each other, and the torque value drastically increases by more than ten times compared to the conventional induction motor. These results indicate that it is possible to realize a compact sized high efficiency HTS motor in a simple structure.

  19. High Ripples Reduction in DTC of Induction Motor by Using a New Reduced Switching Table

    NASA Astrophysics Data System (ADS)

    Mokhtari, Bachir; Benkhoris, Mohamed F.

    2016-05-01

    The direct torque and flux control (DTC) of electrical motors is characterized by ripples of torque and flux. Among the many solutions proposed to reduce them is to use modified switching tables which is very advantageous; because its implementation is easy and requires no additional cost compared to other solutions. This paper proposes a new reduced switching table (RST) to improve the DTC by reducing harmful ripples of torque and flux. This new switching table is smaller than the conventional one (CST) and depends principally at the flux error. This solution is studied by simulation under Matlab/Simulink and experimentally validated on a testbed with DSPACE1103. The results obtained of a DTC with RST applied to a three-phase induction motor (IM) show a good improvement and an effectiveness of proposed solution, the torque ripple decreases about 47% and 3% for the stator flux compared with a basic DTC.

  20. Vectorial Command of Induction Motor Pumping System Supplied by a Photovoltaic Generator

    NASA Astrophysics Data System (ADS)

    Makhlouf, Messaoud; Messai, Feyrouz; Benalla, Hocine

    2011-01-01

    With the continuous decrease of the cost of solar cells, there is an increasing interest and needs in photovoltaic (PV) system applications following standard of living improvements. Water pumping system powered by solar-cell generators are one of the most important applications. The fluctuation of solar energy on one hand, and the necessity to optimise available solar energy on the other, it is useful to develop new efficient and flexible modes to control motors that entrain the pump. A vectorial control of an asynchronous motor fed by a photovoltaic system is proposed. This paper investigates a photovoltaic-electro mechanic chain, composed of a PV generator, DC-AC converter, a vector controlled induction motor and centrifugal pump. The PV generator is forced to operate at its maximum power point by using an appropriate search algorithm integrated in the vector control. The optimization is realized without need to adding a DC-DC converter to the chain. The motor supply is also ensured in all insolation conditions. Simulation results show the effectiveness and feasibility of such an approach.

  1. Torque Ripple Reduction in Direct Torque Control Based Induction Motor using Intelligent Controllers

    NASA Astrophysics Data System (ADS)

    Sudhakar, Ambarapu; Vijaya Kumar, M.

    2015-09-01

    This paper presents intelligent control scheme together with conventional control scheme to overcome the problems with uncertainties in the structure encountered with classical model based design of induction motor drive based on direct torque control (DTC). It allows high dynamic performance to be obtained with very simple hysteresis control scheme. Direct control of the torque and flux is achieved by proper selection of inverter voltage space vector through a lookup table. This paper also presents the application of intelligent controllers like neural network and fuzzy logic controllers to control induction machines with DTC. Intelligent controllers are used to emulate the state selector of the DTC. With implementation of intelligent controllers the system is also verified and proved to be operated stably with reduced torque ripple. The proposed method validity and effectiveness has been verified by computer simulations using Matlab/Simulink®. These results are compared with the ones obtained with a classical DTC using proportional integral speed controller.

  2. Hybrid-secondary uncluttered induction machine

    DOEpatents

    Hsu, John S.

    2001-01-01

    An uncluttered secondary induction machine (100) includes an uncluttered rotating transformer (66) which is mounted on the same shaft as the rotor (73) of the induction machine. Current in the rotor (73) is electrically connected to current in the rotor winding (67) of the transformer, which is not electrically connected to, but is magnetically coupled to, a stator secondary winding (40). The stator secondary winding (40) is alternately connected to an effective resistance (41), an AC source inverter (42) or a magnetic switch (43) to provide a cost effective slip-energy-controlled, adjustable speed, induction motor that operates over a wide speed range from below synchronous speed to above synchronous speed based on the AC line frequency fed to the stator.

  3. Identification of significant intrinsic mode functions for the diagnosis of induction motor fault.

    PubMed

    Cho, Sangjin; Shahriar, Md Rifat; Chong, Uipil

    2014-08-01

    For the analysis of non-stationary signals generated by a non-linear process like fault of an induction motor, empirical mode decomposition (EMD) is the best choice as it decomposes the signal into its natural oscillatory modes known as intrinsic mode functions (IMFs). However, some of these oscillatory modes obtained from a fault signal are not significant as they do not bear any fault signature and can cause misclassification of the fault instance. To solve this issue, a novel IMF selection algorithm is proposed in this work.

  4. Biophysical characterization of the C-terminal region of FliG, an essential rotor component of the Na+-driven flagellar motor.

    PubMed

    Gohara, Mizuki; Kobayashi, Shiori; Abe-Yoshizumi, Rei; Nonoyama, Natsumi; Kojima, Seiji; Asami, Yasuo; Homma, Michio

    2014-02-01

    The bacterial flagellar motor generates a rotational force by the flow of ions through the membrane. The rotational force is generated by the interaction between the cytoplasmic regions of the rotor and the stator. FliG is directly involved in the torque generation of the rotor protein by its interaction. FliG is composed of three domains: the N-terminal, Middle and C-terminal domains, based on its structure. The C-terminal domain of FliG is assumed to be important for the interaction with the stator that generates torque. In this study, using CD spectra, gel filtration chromatography and DSC (differential scanning calorimetry), we characterized the physical properties of the C-terminal domain (G214-Stop) of wild-type (WT) FliG and its non-motile phenotype mutant derivatives (L259Q, L270R and L271P), which were derived from the sodium-driven motor of Vibrio. The CD spectra and gel filtration chromatography revealed a slight difference between the WT and the mutant FliG proteins, but the DSC results suggested a large difference in their stabilities. That structural difference was confirmed by differences in protease sensitivity. Based on these results, we conclude that mutations which confer the non-motile phenotype destabilize the C-terminal domain of FliG.

  5. A Novel Method for Improving Overload Capability of Stand-alone Power System Based on a Flywheel Induction Motor

    NASA Astrophysics Data System (ADS)

    Cheng, Miao-Miao; Kato, Shuhei; Sumitani, Hideo; Shimada, Ryuichi

    Stand-alone power systems are widely used in islands and remote areas. With the rapid advances in the new energy technology, stand-alone power systems have got a rapid development. However, their overload capability is very poor. In this paper, a novel method to improve the overload performance of the stand-alone power system is proposed by using a flywheel induction motor. The flywheel induction motor is composed of a flywheel disk connected to a squirrel cage induction motor. It is controlled to supply the overload power of the stand-alone power supply by charging and discharging. The proposed system is characterized by the following three points: 1) Simple configuration; The flywheel induction motor is directly connected to the inverter-controlled load without any converters. 2) Simple frequency control; The expected active power flow is realized by a small change of the stand-alone power side inverter's output frequency. 3) Low cost system; A decreased power capacity demand for the stand-alone power supply is realized by adding a low cost flywheel induction motor. Experimental results are provided to verify the proposed system.

  6. Détermination de régimes transitoires des moteurs à induction par une nouvelle méthode de couplage des champs magnétiques du stator et du rotor

    NASA Astrophysics Data System (ADS)

    Bock, J. P.; Laporte, B.; Vinsard, G.

    1995-10-01

    A model allowing the effective computation of the transient behaviour of deep squirrel cage induction motors is detailed. The principle of the model is that the coupling between the rotor and the stator is made only by the fundamental space harmonic, the other harmonics are forced to vanish through the air gap. The main interest is that in the time step method only the fundamental space harmonic has to be transferred, which allows larger steps than in a punctual transfer. This method can be used when non linearities exist but it is detailed in the paper in the linear case. Nous présentons la modélisation d'un moteur à induction à cage profonde dont la vitesse est donnée et que l'on alimente, à partir d'un instant donné, par des courants qui sont des fonctions connues du temps. Les champs statoriques et rotoriques sont couplés par leur premier harmonique d'espace. L'intérêt de cette méthode est que seul le premier harmonique d'espace est transporté dans le suivi simultané du mouvement et de l'évolution des courants, ce qui autorise des rotations élémentaires plus importantes et donc un temps de calcul nettement réduit. La méthode, généralisable au cas non linéaire, est développée ici dans le cas linéaire.

  7. Adaptive control schemes for improving dynamic performance of efficiency-optimized induction motor drives.

    PubMed

    Kumar, Navneet; Raj Chelliah, Thanga; Srivastava, S P

    2015-07-01

    Model Based Control (MBC) is one of the energy optimal controllers used in vector-controlled Induction Motor (IM) for controlling the excitation of motor in accordance with torque and speed. MBC offers energy conservation especially at part-load operation, but it creates ripples in torque and speed during load transition, leading to poor dynamic performance of the drive. This study investigates the opportunity for improving dynamic performance of a three-phase IM operating with MBC and proposes three control schemes: (i) MBC with a low pass filter (ii) torque producing current (iqs) injection in the output of speed controller (iii) Variable Structure Speed Controller (VSSC). The pre and post operation of MBC during load transition is also analyzed. The dynamic performance of a 1-hp, three-phase squirrel-cage IM with mine-hoist load diagram is tested. Test results are provided for the conventional field-oriented (constant flux) control and MBC (adjustable excitation) with proposed schemes. The effectiveness of proposed schemes is also illustrated for parametric variations. The test results and subsequent analysis confer that the motor dynamics improves significantly with all three proposed schemes in terms of overshoot/undershoot peak amplitude of torque and DC link power in addition to energy saving during load transitions.

  8. The Experimental Study of Rayleigh-Taylor Instability using a Linear Induction Motor Accelerator

    NASA Astrophysics Data System (ADS)

    Yamashita, Nicholas; Jacobs, Jeffrey

    2009-11-01

    The experiments to be presented utilize an incompressible system of two stratified miscible liquids of different densities that are accelerated in order to produce the Rayleigh-Taylor instability. Three liquid combinations are used: isopropyl alcohol with water, a calcium nitrate solution or a lithium polytungstate solution, giving Atwood numbers of 0.11, 0.22 and 0.57, respectively. The acceleration required to drive the instability is produced by two high-speed linear induction motors mounted to an 8 m tall drop tower. The motors are mounted in parallel and have an effective acceleration length of 1.7 m and are each capable of producing 15 kN of thrust. The liquid system is contained within a square acrylic tank with inside dimensions 76 x76x184 mm. The tank is mounted to an aluminum plate, which is driven by the motors to create constant accelerations in the range of 1-20 g's, though the potential exists for higher accelerations. Also attached to the plate are a high-speed camera and an LED backlight to provide continuous video of the instability. In addition, an accelerometer is used to provide acceleration measurements during each experiment. Experimental image sequences will be presented which show the development of a random three-dimensional instability from an unforced initial perturbation. Measurements of the mixing zone width will be compared with traditional growth models.

  9. Temporary Short Circuit Detection in Induction Motor Winding Using Second Level Haar-Wavelet Transform

    NASA Astrophysics Data System (ADS)

    Asfani, Dimas Anton; Syafaruddin, Dimas Anton; Purnomo, Mauridhi Heri; Hiyama, Takashi

    Faults in induction motor winding can be successfully detected using different motor current signature analysis. However, there still remain some parts where the performance of conventional methods can be improved. In case of the fast Fourier transform (FFT) method, it can only identify the permanent fault, but not the temporary one because the method gives frequency content similar to the normal condition. Moreover, the FFT technique is unable to provide the exact timing information of the fault occurrence. On the other hand, the method based on the first level wavelet transform sometimes gives misleading information, especially in case of starting and ending points of temporary short circuit. For these reasons, this paper comes up with a new method for winding fault detection, which analyzes motor current spectrogram based on extension wavelet analysis, called the second level Haar wavelet transform. The proposed method is able to detect temporary fault with very short duration and low current level with more clear information than that of the first level. Several testing scenarios are presented to confirm the robustness of the proposed method including the provision of time of occurrence information for each case.

  10. Immediate Effects of Kinesiology Taping of Quadriceps on Motor Performance after Muscle Fatigued Induction

    PubMed Central

    Ahn, Ick Keun; Kim, You Lim; Bae, Young-Hyeon; Lee, Suk Min

    2015-01-01

    Objectives. The purpose of this cross-sectional single-blind study was to investigate the immediate effects of Kinesiology taping of quadriceps on motor performance after muscle fatigued induction. Design. Randomized controlled cross-sectional design. Subjects. Forty-five subjects participated in this study. Participants were divided into three groups: Kinesiology taping group, placebo taping group, and nontaping group. Methods. Subjects performed short-term exercise for muscle fatigued induction, followed by the application of each intervention. Peak torque test, one-leg single hop test, active joint position sense test, and one-leg static balance test were carried out before and after the intervention. Results. Peak torque and single-leg hopping distance were significantly increased when Kinesiology taping was applied (p < 0.05). But there were no significant effects on active joint position sense and single-leg static balance. Conclusions. We proved that Kinesiology taping is effective in restoring muscle power reduced after muscle fatigued induction. Therefore, we suggest that Kinesiology taping is beneficial for fatigued muscles. PMID:26246835

  11. Directed Induction of Functional Motor Neuron-Like Cells from Genetically Engineered Human Mesenchymal Stem Cells

    PubMed Central

    Park, Hwan-Woo; Cho, Jung-Sun; Park, Chul-Kyu; Jung, Sung Jun; Park, Chang-Hwan; Lee, Shin-Jae; Oh, Seog Bae; Park, Young-Seok; Chang, Mi-Sook

    2012-01-01

    Cell replacement using stem cells is a promising therapeutic approach to treat degenerative motor neuron (MN) disorders, such as amyotrophic lateral sclerosis and spinal cord injury. Human bone marrow-derived mesenchymal stem cells (hMSCs) are a desirable cell source for autologous cell replacement therapy to treat nervous system injury due to their plasticity, low immunogenicity, and a lower risk of tumor formation than embryonic stem cells. However, hMSCs are inefficient with regards to differentiating into MN-like cells. To solve this limitation, we genetically engineered hMSCs to express MN-associated transcription factors, Olig2 and Hb9, and then treat the hMSCs expressing Olig2 and Hb9 with optimal MN induction medium (MNIM). This method of induction led to higher expression (>30% of total cells) of MN markers. Electrophysiological data revealed that the induced hMSCs had the excitable properties of neurons and were able to form functional connections with muscle fibers in vitro. Furthermore, when the induced hMSCs were transplanted into an injured organotypic rat spinal cord slice culture, an ex vivo model of spinal cord injury, they exhibited characteristics of MNs. The data strongly suggest that induced Olig2/Hb9-expressing hMSCs were clearly reprogrammed and directed toward a MN-like lineage. We propose that methods to induce Olig2 and Hb9, followed by further induction with MNIM have therapeutic potential for autologous cell replacement therapy to treat degenerative MN disorders. PMID:22496912

  12. Controlled Directional Motions of Molecular Vehicles, Rotors, and Motors: From Metallic to Silicon Surfaces, a Strategy to Operate at Higher Temperatures.

    PubMed

    Chérioux, Frédéric; Galangau, Olivier; Palmino, Frank; Rapenne, Gwénaël

    2016-06-17

    In the last decade, many nanomachines with controlled molecular motions have been studied, mainly on metallic surfaces, which are easy to obtain very clean, and are stable over months. However, the studies of mechanical properties of nanomachines are mainly performed at very low temperatures, usually between 5 and 80 K, which prevents any kind of applications. In this Minireview, we will present our strategy to operate at higher temperatures, in particular through the use of semiconducting silicon surfaces. We also review our best achievements in the field through some examples of rotating molecular machines that have been designed, synthesized, and studied in our groups. On metallic surfaces, the nanovehicles are molecules with two or four triptycenes as wheels and the molecular motor is built around a ruthenium organometallic center with a piano-stool geometry and peripheric ferrocenyl groups. On semiconducting silicon surfaces, vehicles are also made from triptycene fragments and the rotor is a pentaphenylbenzene molecule.

  13. End effect analysis of linear induction motor based on the wavelet transform technique

    SciTech Connect

    Mori, Yoshihiko; Torii, Susumu; Ebihara, Daiki

    1999-09-01

    HSST (High Speed Surface Transport) is currently being developed for the railway systems of urban transportation in Japan. It is used in the electromagnetic suspension and short-stator Linear Induction Motor (LIM) for the HSST. The performance of LIM is degraded due to the influence of the end effects. LIM is analyzed using the Fourier series expansion to throw light on this problem. However, to obtain the high-accuracy in this technique, the number of times for calculating is increased. In case of the Wavelet transform technique, as the Wavelet coefficients converge rapidly to zero, this technique has been applied to analyze the end effects of LIM. In this paper, the authors investigated the method for determining of mother wavelet.

  14. Design of a microprocessor based novel braking of three phase induction motor

    SciTech Connect

    Sinha, N.; Laskar, S.H.; Goyal, K.; Nair, P.B.; Sharma, M.K.

    1995-12-31

    This paper describes the development of an efficient braking system suitable for three phase induction motor drives specially driving loads of non-overhauling type. The method incorporates a combination of three braking methods in four states according to the speed range at which the respective methods are most effective, with the result of a smooth and efficient braking. First capacitor self-excitation is applied in stages followed by magnetic braking by double short circuiting and dc injection. Theoretical and experimental results for determining different parameters useful for designing the braking scheme are provided. Lastly microprocessor has been used for proper incorporation of different braking schemes. Dual switching scheme has improved the reliability of the scheme.

  15. Use of an AC induction motor system for producing finger movements in human subjects.

    PubMed

    Proudlock, F A; Scott, J J

    1998-12-01

    This report describes the set-up and evaluation of a novel system for producing precise finger movements, for tests of movement perception. The specifications were to construct a system using commercially available components that were easy to use but which offered both flexibility and also high precision control. The system was constructed around an industrial AC induction motor with an optical encoder, controlled by an AC servo digital control module that could be programmed using a simple, high-level language. This set-up fulfilled the requirements regarding position and velocity control for a range of movements and also the facility for the subject to move the joint voluntarily while still attached to the motor. However a number of problems were encountered, the most serious being the level of vibration and the inability to vary the torque during movements. The vibration was reduced to the point where it did not affect the subject, by the introduction of mechanical dampening using an anti-vibration coupling and a pneumatic splint. The torque control could not be modified during rotation and so the system could only be operated using constant torque for any given movement.

  16. Temperature and Light Control of Three phase Induction Motor Speed Drive by PIC

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader

    2010-06-01

    PIC is a family of Harvard architecture microcontrollers made by Microchip Technology, derived from the PIC1640 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to "Peripheral Interface Controller". PICs are popular with the developers and the hobbyists due to their low cost, wide availability, large user base, extensive collection of application notes, free development tools, and serial programming (and re-programming with flash memory) capability. In modern days, PIC microcontrollers are used in the industrial world to control many types of equipment, ranging from consumer to specialized devices. They have replaced older types of controllers, including microprocessors. Also, there is a growing need for off-line support of a computer's main processor. The demand is going to grow with more equipment uses more intelligence. In the engineering field for instance, PIC has brought a very positive impact in designing an automation control system and controlling industrial machineries. Accordingly, this paper shows the change in the motor speed by the use of PIC in accordance to the light and level of temperature. The project focuses on programming the PIC by embedded software that detects the temperature and light signals and send it to 3 phase induction motor of 240 volt. A theoretical analysis and the practical approach in achieving this work goal have proved that PIC plays an important role in the field of electronics control.

  17. An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs.

    PubMed

    Tabbache, Bekheïra; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-Matthieu; Mamoune, Abdeslam

    2013-11-01

    This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses.

  18. Hybrid Pwm Switching Strategy for a Three-Level Inverter Fed Induction Motor Drive with Open-End Windings

    NASA Astrophysics Data System (ADS)

    Srinivas, S.; Ramachandrasekhar, K.

    2010-06-01

    A dual two-level inverter fed induction motor with open-end windings is capable of generating a three-level output voltage. Several, sine-triangle and space vector pulse width modulation (PWM) switching strategies are presented for the dual-inverter scheme either using space-vector or carrier-based implementation. In this paper, a hybrid PWM switching strategy for the dual-inverter scheme is proposed employing sine-triangle PWM (SPWM) and space vector PWM (SVPWM) for the individual inverters. SPWM is theoretically analyzed and space vector based implementation of SPWM is presented using a simple offset-time concept. This is exploited to implement the hybrid PWM switching strategy for the dual two-level inverter. The implementation of the hybrid PWM switching strategy proposed in this paper do not require any look-up tables, the switching is totally automatic obviating the time-consuming task of sector identification. The implementation of the hybrid PWM scheme requires only the three instantaneous phase reference voltages corresponding to the reference space vector. The third harmonic component in the voltage appearing across the motor phase windings in the induction motor is significantly reduced (by 50%) with the use of the proposed hybrid PWM scheme as compared to the use of the PWM scheme presented earlier. Also, the percentage weighted total harmonic distortion (%WTHD) of the output voltage is significantly reduced in the entire range of speed of the induction motor driven by the dual-inverter scheme.

  19. Motor/generator

    DOEpatents

    Hickam, Christopher Dale

    2008-05-13

    A motor/generator is provided for connecting between a transmission input shaft and an output shaft of a prime mover. The motor/generator may include a motor/generator housing, a stator mounted to the motor/generator housing, a rotor mounted at least partially within the motor/generator housing and rotatable about a rotor rotation axis, and a transmission-shaft coupler drivingly coupled to the rotor. The transmission-shaft coupler may include a clamp, which may include a base attached to the rotor and a plurality of adjustable jaws.

  20. Advanced electric motor technology flux mapping

    NASA Technical Reports Server (NTRS)

    Doane, George B., III; Campbell, Warren; Dean, Garvin

    1993-01-01

    Design of electric motors which fulfill the needs of Thrust Vector Control (TVC) actuators used in large rocket propelled launch vehicles is covered. To accomplish this end the methodology of design is laid out in some detail. In addition a point design of a motor to fulfill the requirements of a certain actuator specified by MSFC is accomplished and reported upon. In the course of this design great stress has been placed on ridding the actuator of internally generated heat. To conduct the heat out of the motor use is made of the unique properties of the in house MSFC designed driving electronics. This property is that as along as they are operated in a quasi-linear mode the electronics nullify the effects of armature inductance as far as the phase of the armature current versus the rotor position is concerned. Actually the additional inductance due to the extended end turns in this design is of benefit because in the shorted armature failure mode the armature current in the fault (caused by the rotor flux sweeping past the armature) is diminished at a given rotor speed when compared to a more conventional motor with lower inductance. The magnetic circuit is analyzed using electromagnetic finite element methods.

  1. Gravitational search algorithm based tuning of a PI speed controller for an induction motor drive

    NASA Astrophysics Data System (ADS)

    Abd Ali, Jamal; Hannan, M. A.; Mohamed, Azah

    2016-03-01

    Proportional-integral (PI)-controller is very useful for controlling speed and mechanical load variables for the three-phase induction motor (TIM) operation. However, the conventional PI-controller has a very exhaustive trial and error procedure for obtaining it is parameters. In this paper, PI speed controller has been improved in it is design technique to suite TIM by utilizing a gravitational search algorithm (GSA) optimization technique. The mean absolute error (MAE) of the speed response has been used as an objective function. An optimal GSA based PI speed controller (GSA-PI) objective function is also employed to tune and minimize the MAE for developing the performance of the TIM in terms of changes speed and mechanical load. This experiment use space vector pulse width modulation (SVPWM) technique to create pulse width modulation for switching devices for three phase bridge inverter. Results obtained from the GSA-PI speed controller are compared with those obtained through particle swarm optimization (PSO) to validate the developed controller. Then it has been proved that the robustness of the GSA-PI speed controller is far better than that of the1 PSO controller in all tested cases in terms of damping capability and transient response under different mechanical loads and speeds.

  2. Fuzzy virtual reference model sensorless tracking control for linear induction motors.

    PubMed

    Hung, Cheng-Yao; Liu, Peter; Lian, Kuang-Yow

    2013-06-01

    This paper introduces a fuzzy virtual reference model (FVRM) synthesis method for linear induction motor (LIM) speed sensorless tracking control. First, we represent the LIM as a Takagi-Sugeno fuzzy model. Second, we estimate the immeasurable mover speed and secondary flux by a fuzzy observer. Third, to convert the speed tracking control into a stabilization problem, we define the internal desired states for state tracking via an FVRM. Finally, by solving a set of linear matrix inequalities (LMIs), we obtain the observer gains and the control gains where exponential convergence is guaranteed. The contributions of the approach in this paper are threefold: 1) simplified approach--speed tracking problem converted into stabilization problem; 2) omit need of actual reference model--FVRM generates internal desired states; and 3) unification of controller and observer design--control objectives are formulated into an LMI problem where powerful numerical toolboxes solve controller and observer gains. Finally, experiments are carried out to verify the theoretical results and show satisfactory performance both in transient response and robustness.

  3. Comparison of experimental and theoretical reaction rail currents, rail voltages, and airgap fields for the linear induction motor research vehicle

    NASA Technical Reports Server (NTRS)

    Elliott, D. G.

    1977-01-01

    Measurements of reaction rail currents, reaction rail voltages, and airgap magnetic fields in tests of the Linear Induction Motor Research Vehicle (LIMRV) were compared with theoretical calculations from the mesh/matrix theory. It was found that the rail currents and magnetic fields predicted by the theory are within 20 percent of the measured currents and fields at most motor locations in most of the runs, but differ by as much as a factor of two in some cases. The most consistent difference is a higher experimental than theoretical magnetic field near the entrance of the motor and a lower experimental than theoretical magnetic field near the exit. The observed differences between the theoretical and experimental magnetic fields and currents do not account for the differences of as much as 26 percent between the theoretical and experimental thrusts.

  4. Insulation Deterioration Detection by Zero-Sequence Current Analysis for Induction Motors

    NASA Astrophysics Data System (ADS)

    Iwanaga, Hideki; Inujima, Hiroshi

    Insulation tests for the stator coil, which decides the motor life, are carried out once several years in power and industrial plant. In the case of high voltage (HV) motors, insulation failure may adversely affect plant operation. Hence, maintenance activities, including insulation tests, research on insulation deterioration, and online Partial Discharge (PD) monitoring, are actively pursued for HV motors. On the other hand, the maintenance of low voltage (LV) motors is restricted to breakdown maintenance (BDM) because (1) a large number of LV motors are in operation in plants and (2) maintenance activities are relatively more expensive than those for HV motors. In this paper, the results of a study on insulation deterioration detection for LV motors are presented. For the deterioration detection, the deference in Zero-Sequence current waveforms between normal conditions and fault conditions is analyzed. This method helps in decreasing the maintenance cost and in online insulation diagnosis for LV motors.

  5. About the Power Generation Confirmation of the Induction Motor and the Influence on the Islanding Detection Device

    NASA Astrophysics Data System (ADS)

    Igarashi, Hironobu; Sato, Takashi; Miyamoto, Kazunori; Kurokawa, Kousuke

    The photovoltaic generation system must have protection device and islanding detection devices to connect with utility line of the electric power company. It is regulated in the technological requirement guideline and the electric equipment technology standard that the country provides. The islanding detection device detected purpose install for blackout due to the accident occurrence of the earth fault and the short-circuit in the utility line. When the islanding detection device detects the power blackout, it is necessary to stop the photovoltaic generation system immediately. If the photovoltaic generation system is not stopped immediately, electricity comes to charge the utility power line very at risk. We had already known that the islanding detection device can't detect the islanding phenomenon, if is there the induction motor in the loads. Authors decided to investigate the influence that the induction motors gave to the islanding detection device. The result was the load condition that the induction motors changed generator the voltage is restraining. Moreover, it was clarified that the time of the islanding was long compared with the load condition of not changing into the state of the generator. The value changes into the reactance of the induction motors according to the frequency change after the supply of electric power line stops. The frequency after the supply of electric power line stops changes for the unbalance the reactive power by the effect of the power rate constancy control with PLL of the power conditioner. However, the induction motors is also to the changing frequency, makes amends for the amount of reactive power, and the change in the frequency after the supply of electric power line stops as a result is controlled. When the frequency changed after the supply of electric power line stopped, it was clarified of the action on the direction where it made amends from the change of the constant for the amount of an invalid electric power, and

  6. Induction of human umbilical Wharton's jelly-derived mesenchymal stem cells toward motor neuron-like cells.

    PubMed

    Bagher, Zohreh; Ebrahimi-Barough, Somayeh; Azami, Mahmoud; Mirzadeh, Hamid; Soleimani, Mansooreh; Ai, Jafar; Nourani, Mohammad Reza; Joghataei, Mohammad Taghi

    2015-10-01

    The most important property of stem cells from different sources is the capacity to differentiate into various cells and tissue types. However, problems including contamination, normal karyotype, and ethical issues cause many limitations in obtaining and using these cells from different sources. The cells in Wharton's jelly region of umbilical cord represent a pool source of primitive cells with properties of mesenchymal stem cells (MSCs). The aim of this study was to determine the potential of human Wharton's jelly-derived mesenchymal stem cells (WJMSCs) for differentiation to motor neuron cells. WJMSCs were induced to differentiate into motor neuron-like cells by using different signaling molecules and neurotrophic factors in vitro. Differentiated neurons were then characterized for expression of motor neuron markers including nestin, PAX6, NF-H, Islet 1, HB9, and choline acetyl transferase (ChAT) by quantitative reverse transcription PCR and immunocytochemistry. Our results showed that differentiated WJMSCs could significantly express motor neuron biomarkers in RNA and protein levels 15 d post induction. These results suggested that WJMSCs can differentiate to motor neuron-like cells and might provide a potential source in cell therapy for neurodegenerative disease.

  7. Electrostatic generator/motor having rotors of varying thickness and a central stator electrically connected together into two groups

    DOEpatents

    Post, Richard F.

    2010-11-16

    A sub-module consists of a set of two outer sets of stationary fan-blade-shaped sectors. These outer sectors include conductive material and are maintained at ground potential in several examples. Located midway between them is a set of stationary sector plates with each plate being electrically insulated from the others. An example provides that the inner sector plates are connected together alternately, forming two groups of parallel-connected condensers that are then separately connected, through high charging circuit resistances, to a source of DC potential with respect to ground, with an additional connecting lead being provided for each group to connect their output as an AC output to a load. These same leads can he used, when connected to a driver circuit, to produce motor action.

  8. The large pursuit rotor.

    PubMed

    Williams, L R; Grbin, I R

    1976-09-01

    The question of whether certain phenomena that occur on the conventional rotary pursuit and other small apparatus also appear on a gross motor task was examined using a large pursuit rotor that required whole-body movements. College males (n=29) were given 90 10-sec trials over three consecutive days with 30 trials of continuous practice per day. The existence of reactive inhibition, reminiscence, and warmup decrement was confirmed, indicating that common mechanisms underlie both fine and gross bodily movements. In addition, the substantial amounts of learning and the high reliabilities for performance and learning indicated that the present apparatus has considerable potential for motor-learning research.

  9. Automatic fault feature extraction of mechanical anomaly on induction motor bearing using ensemble super-wavelet transform

    NASA Astrophysics Data System (ADS)

    He, Wangpeng; Zi, Yanyang; Chen, Binqiang; Wu, Feng; He, Zhengjia

    2015-03-01

    Mechanical anomaly is a major failure type of induction motor. It is of great value to detect the resulting fault feature automatically. In this paper, an ensemble super-wavelet transform (ESW) is proposed for investigating vibration features of motor bearing faults. The ESW is put forward based on the combination of tunable Q-factor wavelet transform (TQWT) and Hilbert transform such that fault feature adaptability is enabled. Within ESW, a parametric optimization is performed on the measured signal to obtain a quality TQWT basis that best demonstrate the hidden fault feature. TQWT is introduced as it provides a vast wavelet dictionary with time-frequency localization ability. The parametric optimization is guided according to the maximization of fault feature ratio, which is a new quantitative measure of periodic fault signatures. The fault feature ratio is derived from the digital Hilbert demodulation analysis with an insightful quantitative interpretation. The output of ESW on the measured signal is a selected wavelet scale with indicated fault features. It is verified via numerical simulations that ESW can match the oscillatory behavior of signals without artificially specified. The proposed method is applied to two engineering cases, signals of which were collected from wind turbine and steel temper mill, to verify its effectiveness. The processed results demonstrate that the proposed method is more effective in extracting weak fault features of induction motor bearings compared with Fourier transform, direct Hilbert envelope spectrum, different wavelet transforms and spectral kurtosis.

  10. Direct Torque Control with Full Order Stator Flux Observer for Dual-Three Phase Induction Motor Drives

    NASA Astrophysics Data System (ADS)

    Farina, Francesco; Bojoi, Radu; Tenconi, Alberto; Profumo, Francesco

    A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper. The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototype.

  11. Application of power spectrum, cepstrum, higher order spectrum and neural network analyses for induction motor fault diagnosis

    NASA Astrophysics Data System (ADS)

    Liang, B.; Iwnicki, S. D.; Zhao, Y.

    2013-08-01

    The power spectrum is defined as the square of the magnitude of the Fourier transform (FT) of a signal. The advantage of FT analysis is that it allows the decomposition of a signal into individual periodic frequency components and establishes the relative intensity of each component. It is the most commonly used signal processing technique today. If the same principle is applied for the detection of periodicity components in a Fourier spectrum, the process is called the cepstrum analysis. Cepstrum analysis is a very useful tool for detection families of harmonics with uniform spacing or the families of sidebands commonly found in gearbox, bearing and engine vibration fault spectra. Higher order spectra (HOS) (also known as polyspectra) consist of higher order moment of spectra which are able to detect non-linear interactions between frequency components. For HOS, the most commonly used is the bispectrum. The bispectrum is the third-order frequency domain measure, which contains information that standard power spectral analysis techniques cannot provide. It is well known that neural networks can represent complex non-linear relationships, and therefore they are extremely useful for fault identification and classification. This paper presents an application of power spectrum, cepstrum, bispectrum and neural network for fault pattern extraction of induction motors. The potential for using the power spectrum, cepstrum, bispectrum and neural network as a means for differentiating between healthy and faulty induction motor operation is examined. A series of experiments is done and the advantages and disadvantages between them are discussed. It has been found that a combination of power spectrum, cepstrum and bispectrum plus neural network analyses could be a very useful tool for condition monitoring and fault diagnosis of induction motors.

  12. A New Modulation Strategy for Unbalanced Two Phase Induction Motor Drives Using a Three-Leg Voltage Source Inverter

    NASA Astrophysics Data System (ADS)

    Sinthusonthishat, S.; Kinnares, V.

    This paper proposes a new modulation scheme providing unbalanced output terminal voltages of a standard three-leg voltage source inverter (VSI) for unsymmetrical type two-phase induction motors. This strategy allows a control method of the output voltages with typically constant V/Hz for a main winding and with voltage boost to compensate magnitude of current for an auxiliary winding. Harmonic voltage characteristics and the motor performance are investigated under a wide range of operating conditions. Practical verification is presented to confirm correctness and capabilities of the proposed technique. All results are compared to those of a conventional two-leg half bridge topology. The results show that the simulation results well agree with the experimental ones, and also the proposed scheme is superior to the conventional drive.

  13. Induction of plasticity in the human motor cortex by pairing an auditory stimulus with TMS.

    PubMed

    Sowman, Paul F; Dueholm, Søren S; Rasmussen, Jesper H; Mrachacz-Kersting, Natalie

    2014-01-01

    Acoustic stimuli can cause a transient increase in the excitability of the motor cortex. The current study leverages this phenomenon to develop a method for testing the integrity of auditorimotor integration and the capacity for auditorimotor plasticity. We demonstrate that appropriately timed transcranial magnetic stimulation (TMS) of the hand area, paired with auditorily mediated excitation of the motor cortex, induces an enhancement of motor cortex excitability that lasts beyond the time of stimulation. This result demonstrates for the first time that paired associative stimulation (PAS)-induced plasticity within the motor cortex is applicable with auditory stimuli. We propose that the method developed here might provide a useful tool for future studies that measure auditory-motor connectivity in communication disorders.

  14. A fuzzy-based approach for open-transistor fault diagnosis in voltage-source inverter induction motor drives

    NASA Astrophysics Data System (ADS)

    Zhang, Jianghan; Luo, Hui; Zhao, Jin; Wu, Feng

    2015-02-01

    This paper develops a novel method for the detection and isolation of open-transistor faults in voltage-source inverters feeding induction motors. Based on analyzing the load currents trajectories after Concordia transformation, six diagnostic signals each of which indicates a certain switch are extracted and a fuzzy rule base is designed to perform fuzzy reasoning in order to detect and isolate 21 fault modes including single- and double-transistor faults. In addition, the fuzzy rules are rearranged and each of them is set to a reasonable value representing the fault modes. The simulation and experiment are carried out to demonstrate the effectiveness of the proposed fuzzy approach.

  15. Motor control for a brushless DC motor

    NASA Technical Reports Server (NTRS)

    Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

    1985-01-01

    This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

  16. Torsional Vibration Analysis of Reciprocating Compressor Trains driven by Induction Motors

    NASA Astrophysics Data System (ADS)

    Brunelli, M.; Fusi, A.; Grasso, F.; Pasteur, F.; Ussi, A.

    2015-08-01

    The dynamic study of electric motor driven compressors, for Oil&Gas (O&G) applications, are traditionally performed in two steps separating the mechanical and the electrical systems. The packager conducts a Torsional Vibration Analysis (TVA) modeling the mechanical system with a lumped parameter scheme, without taking into account the electrical part. The electric motor supplier later performs a source current pulsation analysis on the electric motor system, based on the TVA results. The mechanical and the electrical systems are actually linked by the electromagnetic effect. The effect of the motor air-gap on TVA has only recently been taken into account by adding a spring and a damper between motor and ground in the model. This model is more accurate than the traditional one, but is applicable only to the steady-state condition and still fails to consider the reciprocal effects between the two parts of the system. In this paper the torsional natural frequencies calculated using both the traditional and the new model have been compared. Furthermore, simulation of the complete system has been achieved through the use of LMS AMESim, multi-physics, one-dimensional simulation software that simultaneously solves the shafts rotation and electric motor voltage equation. Finally, the transient phenomena that occur during start-up have been studied.

  17. Sensored Field Oriented Control of a Robust Induction Motor Drive Using a Novel Boundary Layer Fuzzy Controller

    PubMed Central

    Saghafinia, Ali; Ping, Hew Wooi; Uddin, Mohammad Nasir

    2013-01-01

    Physical sensors have a key role in implementation of real-time vector control for an induction motor (IM) drive. This paper presents a novel boundary layer fuzzy controller (NBLFC) based on the boundary layer approach for speed control of an indirect field-oriented control (IFOC) of an induction motor (IM) drive using physical sensors. The boundary layer approach leads to a trade-off between control performances and chattering elimination. For the NBLFC, a fuzzy system is used to adjust the boundary layer thickness to improve the tracking performance and eliminate the chattering problem under small uncertainties. Also, to eliminate the chattering under the possibility of large uncertainties, the integral filter is proposed inside the variable boundary layer. In addition, the stability of the system is analyzed through the Lyapunov stability theorem. The proposed NBLFC based IM drive is implemented in real-time using digital signal processor (DSP) board TI TMS320F28335. The experimental and simulation results show the effectiveness of the proposed NBLFC based IM drive at different operating conditions.

  18. Active magnetic suspension in main magnetic field of electric motor

    NASA Astrophysics Data System (ADS)

    Urusov, I. D.; Galkin, V. I.; Likhoshvay, I. P.

    1985-10-01

    An active magnetic suspension for the rotor of an electric motor is considered, especially in small or miniature high-speed devices such as gyros, microturbomachines, and machine-tool spindle drives where it would eliminate the need for extra bearings and contribute to size and weight reduction. A disk-type rotor made of a ferromagnetic material is located horizontally inside the bore of a vertical stator so that weight and external loads compensate the magnetic pull upward. This pull is generated by the magnetic field in the air gap and can be automatically controlled by an electronic feedback circuit which regulates the stator input voltage depending on the rotor position along the stator bore, with a displacement transducer on the rotor indicating the position. The performance of such a suspension with automatic control in a 3-phase induction motor is analyzed on the basis of the system of differential equations describing the behavior of the electromechanical system during axial oscillations of the rotor, assuming a constant rotor speed during the transient periods.

  19. Multiple stage miniature stepping motor

    DOEpatents

    Niven, William A.; Shikany, S. David; Shira, Michael L.

    1981-01-01

    A stepping motor comprising a plurality of stages which may be selectively activated to effect stepping movement of the motor, and which are mounted along a common rotor shaft to achieve considerable reduction in motor size and minimum diameter, whereby sequential activation of the stages results in successive rotor steps with direction being determined by the particular activating sequence followed.

  20. Development of Ulta-Efficient Electric Motors

    SciTech Connect

    Shoykhet, B.; Schiferl, R.; Duckworth, R.; Rey, C.M.; Schwenterly, S.W.; Gouge, M.J.

    2008-05-01

    Electric motors utilize a large amount of electrical energy in utility and industrial applications. Electric motors constructed with high temperature superconducting (HTS) materials have the potential to dramatically reduce electric motor size and losses. HTS motors are best suited for large motor applications at ratings above 1000 horsepower (hp), where the energy savings from the efficiency improvement can overcome the additional power required to keep the superconductors on the rotor cooled. Large HTS based motors are expected to be half the volume and have half the losses of conventional induction motors of the same rating. For a 5000 hp industrial motor, this energy savings can result in $50,000 in operating cost savings over the course of a single year of operation. Since large horsepower motors utilize (or convert) about 30% of the electrical power generated in the United States and about 70% of large motors are candidates for replacement by HTS motors, the annual energy savings potential through the utilization of HTS motors can be up to $1 Billion in the United States alone. Research in the application of HTS materials to electric motors has lead to a number of HTS motor prototypes yet no industrial HTS motor product has yet been introduced. These motor demonstrations have been synchronous motors with HTS field windings, on the rotor. Figure 1-1 shows a solid model rendering of this type of motor. The rotor winding is made with HTS coils that are held at cryogenic temperature by introducing cooling fluid from the cryocooler to the rotor through a transfer coupling. The stator winding is made of copper wire. The HTS winding is thermally isolated from the warm armature and motor shafts by a vacuum insulation space and through the use of composite torque tubes. The stator in Figure 1-1 is an air core stator in that the stator teeth and a small part of the yoke is made up of nonmagnetic material so the magnetic fields distribute themselves as if in air

  1. Harmonic reduction of Direct Torque Control of six-phase induction motor.

    PubMed

    Taheri, A

    2016-07-01

    In this paper, a new switching method in Direct Torque Control (DTC) of a six-phase induction machine for reduction of current harmonics is introduced. Selecting a suitable vector in each sampling period is an ordinal method in the ST-DTC drive of a six-phase induction machine. The six-phase induction machine has 64 voltage vectors and divided further into four groups. In the proposed DTC method, the suitable voltage vectors are selected from two vector groups. By a suitable selection of two vectors in each sampling period, the harmonic amplitude is decreased more, in and various comparison to that of the ST-DTC drive. The harmonics loss is greater reduced, while the electromechanical energy is decreased with switching loss showing a little increase. Spectrum analysis of the phase current in the standard and new switching table DTC of the six-phase induction machine and determination for the amplitude of each harmonics is proposed in this paper. The proposed method has a less sampling time in comparison to the ordinary method. The Harmonic analyses of the current in the low and high speed shows the performance of the presented method. The simplicity of the proposed method and its implementation without any extra hardware is other advantages of the proposed method. The simulation and experimental results show the preference of the proposed method.

  2. Molecular Rotors

    DTIC Science & Technology

    2006-10-31

    Zack Murray No Faith Jordan No Charles Hagerdorn No Elizabeth Baker, No Mathew Myers No Leah A. Edelman No William T. Gathright No Bill Bockrath No...ligand could impact the construction of rotor arrays. Consequently, VASP calculations were performed in collaboration with Dr. Jeffrey Reimers of

  3. Position-and Velocity- Sensorless Control of Cylindrical Brushless DC Motors Driven by Sinusoidal Current at Low Speed Using Eddy Current

    NASA Astrophysics Data System (ADS)

    Takashima, Hiroshi; Tomita, Mutuwo; Chen, Zhiqian; Satoh, Mitsuhiko; Doki, Shinji; Okuma, Shigeru

    This paper proposes to paste non-magnetic materials on the rotor surface of a cylindrical brushless DC motor and to use the model including the extended e.m.f. for sensorless control. In the proposed method, the inductance changes depending on the rotor position because of eddy currents, which flow on the non-magnetic material at high frequency. The rotor position can be estimated at standstill and at low speeds. The simulation results show that the proposed method is very useful.

  4. Diagnosis of broken-bars fault in induction machines using higher order spectral analysis.

    PubMed

    Saidi, L; Fnaiech, F; Henao, H; Capolino, G-A; Cirrincione, G

    2013-01-01

    Detection and identification of induction machine faults through the stator current signal using higher order spectra analysis is presented. This technique is known as motor current signature analysis (MCSA). This paper proposes two higher order spectra techniques, namely the power spectrum and the slices of bi-spectrum used for the analysis of induction machine stator current leading to the detection of electrical failures within the rotor cage. The method has been tested by using both healthy and broken rotor bars cases for an 18.5 kW-220 V/380 V-50 Hz-2 pair of poles induction motor under different load conditions. Experimental signals have been analyzed highlighting that bi-spectrum results show their superiority in the accurate detection of rotor broken bars. Even when the induction machine is rotating at a low level of shaft load (no-load condition), the rotor fault detection is efficient. We will also demonstrate through the analysis and experimental verification, that our proposed proposed-method has better detection performance in terms of receiver operation characteristics (ROC) curves and precision-recall graph.

  5. Engineering and Design: Selecting Reaction-Type Hydraulic Turbines and Pump Turbines and Hydroelectric Generators and Generator-Motors

    DTIC Science & Technology

    2007-11-02

    turbines must k designed to suit the specific range of conditions under which they will operate, each generator and generator- motor is unique in that the... conditions . Continuous, heavy-duty amortisseur windings me required for generator-rotors which are to be started as induction motors . (2) ~rtisseur...cubic feet, and the available water horsepwer is: WHP = wQH 550 d. The amount of power that can be prducd under pradical working conditions is less

  6. Separators for flywheel rotors

    DOEpatents

    Bender, D.A.; Kuklo, T.C.

    1998-07-07

    A separator forms a connection between the rotors of a concentric rotor assembly. This separator allows for the relatively free expansion of outer rotors away from inner rotors while providing a connection between the rotors that is strong enough to prevent disassembly. The rotor assembly includes at least two rotors referred to as inner and outer flywheel rings or rotors. This combination of inner flywheel ring, separator, and outer flywheel ring may be nested to include an arbitrary number of concentric rings. The separator may be a segmented or continuous ring that abuts the ends of the inner rotor and the inner bore of the outer rotor. It is supported against centrifugal loads by the outer rotor and is affixed to the outer rotor. The separator is allowed to slide with respect to the inner rotor. It is made of a material that has a modulus of elasticity that is lower than that of the rotors. 10 figs.

  7. Separators for flywheel rotors

    DOEpatents

    Bender, Donald A.; Kuklo, Thomas C.

    1998-01-01

    A separator forms a connection between the rotors of a concentric rotor assembly. This separator allows for the relatively free expansion of outer rotors away from inner rotors while providing a connection between the rotors that is strong enough to prevent disassembly. The rotor assembly includes at least two rotors referred to as inner and outer flywheel rings or rotors. This combination of inner flywheel ring, separator, and outer flywheel ring may be nested to include an arbitrary number of concentric rings. The separator may be a segmented or continuous ring that abuts the ends of the inner rotor and the inner bore of the outer rotor. It is supported against centrifugal loads by the outer rotor and is affixed to the outer rotor. The separator is allowed to slide with respect to the inner rotor. It is made of a material that has a modulus of elasticity that is lower than that of the rotors.

  8. Variable-frequency synchronous motor drives for electric vehicles

    SciTech Connect

    Chalmers, B.J.; Musaba, L.; Gosden, D.F.

    1996-07-01

    The performance capability envelope of a variable-frequency, permanent-magnet synchronous motor drive with field weakening is dependent upon the product of maximum current and direct-axis inductance. To obtain a performance characteristic suitable for a typical electric vehicle drive, in which short-term increase of current is applied, it is necessary to design an optimum value of direct-axis inductance. The paper presents an analysis of a hybrid motor design which uses a two-part rotor construction comprising a surface-magnet part and an axially laminated reluctance part. This arrangement combines the properties of all other types of synchronous motor and offers a greater choice of design variables. It is shown that the desired form of performance may be achieved when the high-inductance axis of the reluctance part is arranged to lead the magnet axis by 90{degree} (elec.).

  9. Variable-frequency synchronous motor drives for electric vehicles

    SciTech Connect

    Chalmers, B.J.; Musaba, L.; Gosden, D.F.

    1995-12-31

    The performance capability envelope of a variable-frequency, permanent-magnet synchronous motor drive with field weakening is dependent upon the product of maximum current and direct-axis inductance. To obtain a performance characteristic suitable for a typical electric vehicle drive, in which short-term increase of current is applied, it is necessary to design an optimum value of direct-axis inductance. The paper presents an analysis of a hybrid motor design which uses a two-part rotor construction comprising a surface-magnet part and an axially-laminated reluctance part. This arrangement combines the properties of all other types of synchronous motor and offers a greater choice of design variables. It is shown that the desired form of performance may be achieved when the high-inductance axis of the reluctance part is arranged to lead the magnet axis by 90{degree} (elec.).

  10. Support vector machine based decision for mechanical fault condition monitoring in induction motor using an advanced Hilbert-Park transform.

    PubMed

    Ben Salem, Samira; Bacha, Khmais; Chaari, Abdelkader

    2012-09-01

    In this work we suggest an original fault signature based on an improved combination of Hilbert and Park transforms. Starting from this combination we can create two fault signatures: Hilbert modulus current space vector (HMCSV) and Hilbert phase current space vector (HPCSV). These two fault signatures are subsequently analysed using the classical fast Fourier transform (FFT). The effects of mechanical faults on the HMCSV and HPCSV spectrums are described, and the related frequencies are determined. The magnitudes of spectral components, relative to the studied faults (air-gap eccentricity and outer raceway ball bearing defect), are extracted in order to develop the input vector necessary for learning and testing the support vector machine with an aim of classifying automatically the various states of the induction motor.

  11. Nonlinear SVM-DTC for induction motor drive using input-output feedback linearization and high order sliding mode control.

    PubMed

    Ammar, Abdelkarim; Bourek, Amor; Benakcha, Abdelhamid

    2017-03-01

    This paper presents a nonlinear Direct Torque Control (DTC) strategy with Space Vector Modulation (SVM) for an induction motor. A nonlinear input-output feedback linearization (IOFL) is implemented to achieve a decoupled torque and flux control and the SVM is employed to reduce high torque and flux ripples. Furthermore, the control scheme performance is improved by inserting a super twisting speed controller in the outer loop and a load torque observer to enhance the speed regulation. The combining of dual nonlinear strategies ensures a good dynamic and robustness against parameters variation and disturbance. The system stability has been analyzed using Lyapunov stability theory. The effectiveness of the control algorithm is investigated by simulation and experimental validation using Matlab/Simulink software with real-time interface based on dSpace 1104.

  12. DSP-based adaptive backstepping using the tracking errors for high-performance sensorless speed control of induction motor drive.

    PubMed

    Zaafouri, Abderrahmen; Ben Regaya, Chiheb; Ben Azza, Hechmi; Châari, Abdelkader

    2016-01-01

    This paper presents a modified structure of the backstepping nonlinear control of the induction motor (IM) fitted with an adaptive backstepping speed observer. The control design is based on the backstepping technique complemented by the introduction of integral tracking errors action to improve its robustness. Unlike other research performed on backstepping control with integral action, the control law developed in this paper does not propose the increase of the number of system state so as not increase the complexity of differential equations resolution. The digital simulation and experimental results show the effectiveness of the proposed control compared to the conventional PI control. The results analysis shows the characteristic robustness of the adaptive control to disturbances of the load, the speed variation and low speed.

  13. Reward improves long-term retention of a motor memory through induction of offline memory gains

    PubMed Central

    Abe, Mitsunari; Schambra, Heidi; Wassermann, Eric M; Luckenbaugh, Dave; Schweighofer, Nicolas; Cohen, Leonardo G

    2011-01-01

    Summary In humans, training in which good performance is rewarded or bad performance punished results in transient behavioral improvements [1–3]. Their relative effects on consolidation and long-term retention, critical behavioral stages for successful learning [4, 5], are not known. Here, we investigated the effects of reward and punishment on these different stages of human motor skill learning. We studied healthy subjects who trained on a motor task under rewarded, punished, or neutral control conditions. Performance was tested before, and immediately, 6 hs, 24 hs and 30 days after training in the absence of reward or punishment. Performance improvements immediately after training were comparable in the three groups. At 6 hs, the rewarded group maintained performance gains while the other two groups experienced significant forgetting. At 24 hs, the reward group showed significant offline (posttraining) improvements while the other two groups did not. At 30 days, the rewarded group retained the gains identified at 24 hs, while the other two groups experienced significant forgetting. We conclude that training under rewarded conditions is more effective than training under punished or neutral conditions in eliciting lasting motor learning, an advantage driven by offline memory gains that persist over time. PMID:21419628

  14. Blood Pump Having a Magnetically Suspended Rotor

    NASA Technical Reports Server (NTRS)

    Antaki, James F. (Inventor); Paden, Bradley (Inventor); Burgreen, Gregory (Inventor); Groom, Nelson J. (Inventor)

    2002-01-01

    A blood pump preferably has a magnetically suspended rotor that rotates within a housing. The rotor may rotate about a stator disposed within the housing. Radial magnetic bearings may be defined within the stator and the rotor in order to suspend the rotor. The radial magnetic bearings may be passive magnetic bearings that include permanent magnets disposed within the stator and the rotor or active magnetic bearings. The pump may further include an axial magnetic bearing that may be either a passive or an active magnetic bearing. A motor that drives the rotor may be disposed within the housing in order to more easily dissipate heat generated by the motor. A primary flow path is defined between the rotor and the stator, and a secondary flow path is defined between the stator and the rotor. Preferably, a substantial majority of blood passes through the primary flow path. The secondary flow path is large enough so that it provides adequate flushing of the secondary flow path while being small enough to permit efficient operation of the radial magnet bearings across the secondary flow path.

  15. Blood Pump Having a Magnetically Suspended Rotor

    NASA Technical Reports Server (NTRS)

    Antaki, James F. (Inventor); Paden, Bradley (Inventor); Burgreen, Gregory (Inventor); Groom, Nelson J. (Inventor)

    2001-01-01

    A blood pump preferably has a magnetically suspended rotor that rotates within a housing. The rotor may rotate about a stator disposed within the housing. Radial magnetic bearings may be defined within the stator and the rotor in order to suspend the rotor. The radial magnetic bearings may be passive magnetic bearings that include permanent magnets disposed within the stator and the rotor or active magnetic bearings. The pump may further include an axial magnetic bearing that may be either a passive or an active magnetic bearing. A motor that drives the rotor may be disposed within the housing in order to more easily dissipate heat generated by the motor. A primary flow path is defined between the rotor and the stator, and a secondary flow path is defined between the stator and the rotor. Preferably, a substantial majority of blood passes through the primary flow path. The secondary flow path is large enough so that it provides adequate flushing of the secondary flow path while being small enough to permit efficient operation of the radial magnet bearings across the secondary flow path.

  16. Wireless Sensors System for Broken Rotor bar Fault Monitoring using Wavelet Analysis

    NASA Astrophysics Data System (ADS)

    Rezazadeh Mehrjou, Mohammad; Mariun, Norman; Karami, Mahdi; Misron, Norhisam; Amran Mohd Radzi, Mohd

    2015-11-01

    Accurate condition monitoring prevents unexpected failures in electrical systems including induction machines, and hence improves their performance significantly. To enhance the reliability of condition monitoring systems, wireless sensor systems are developed. In the recent years, researchers have placed considerable emphasis on developing cost-effective scheme using wireless sensor systems for fault diagnosis of equipments in industry. As broken rotor bar is one of the main causes of malfunction in electrical motors, this paper proposes a method for early detection of this failure in induction machines using wireless sensor system. In this respect, a test bed is developed where a sensor measures the motor current and then a microcontroller connected to this current sensor read and send the data to wireless sensor for remote real time data analysis. In the receiver unit, a Lab VIEW based program is developed to store data in a database and MATLAB is used for signal processing and fault.

  17. Substantially parallel flux uncluttered rotor machines

    SciTech Connect

    Hsu, John S.

    2012-12-11

    A permanent magnet-less and brushless synchronous system includes a stator that generates a magnetic rotating field when sourced by polyphase alternating currents. An uncluttered rotor is positioned within the magnetic rotating field and is spaced apart from the stator. An excitation core is spaced apart from the stator and the uncluttered rotor and magnetically couples the uncluttered rotor. The brushless excitation source generates a magnet torque by inducing magnetic poles near an outer peripheral surface of the uncluttered rotor, and the stator currents also generate a reluctance torque by a reaction of the difference between the direct and quadrature magnetic paths of the uncluttered rotor. The system can be used either as a motor or a generator

  18. Motor degradation prediction methods

    SciTech Connect

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  19. Induction of Long-term Depression-like Plasticity by Pairings of Motor Imagination and Peripheral Electrical Stimulation.

    PubMed

    Jochumsen, Mads; Signal, Nada; Nedergaard, Rasmus W; Taylor, Denise; Haavik, Heidi; Niazi, Imran K

    2015-01-01

    Long-term depression (LTD) and long-term potentiation (LTP)-like plasticity are models of synaptic plasticity which have been associated with memory and learning. The induction of LTD and LTP-like plasticity, using different stimulation protocols, has been proposed as a means of addressing abnormalities in cortical excitability associated with conditions such as focal hand dystonia and stroke. The aim of this study was to investigate whether the excitability of the cortical projections to the tibialis anterior (TA) muscle could be decreased when dorsiflexion of the ankle joint was imagined and paired with peripheral electrical stimulation (ES) of the nerve supplying the antagonist soleus muscle. The effect of stimulus timing was evaluated by comparing paired stimulation timed to reach the cortex before, at and after the onset of imagined movement. Fourteen healthy subjects participated in six experimental sessions held on non-consecutive days. The timing of stimulation delivery was determined offline based on the contingent negative variation (CNV) of electroencephalography brain data obtained during imagined dorsiflexion. Afferent stimulation was provided via a single pulse ES to the peripheral nerve paired, based on the CNV, with motor imagination of ankle dorsiflexion. A significant decrease (P = 0.001) in the excitability of the cortical projection of TA was observed when the afferent volley from the ES of the tibial nerve (TN) reached the cortex at the onset of motor imagination based on the CNV. When TN stimulation was delivered before (P = 0.62), or after (P = 0.23) imagined movement onset there was no significant effect. Nor was a significant effect found when ES of the TN was applied independent of imagined movement (P = 0.45). Therefore, the excitability of the cortical projection to a muscle can be inhibited when ES of the nerve supplying the antagonist muscle is precisely paired with the onset of imagined movement.

  20. The sensory-motor theory of rhythm and beat induction 20 years on: a new synthesis and future perspectives

    PubMed Central

    Todd, Neil P. M.; Lee, Christopher S.

    2015-01-01

    Some 20 years ago Todd and colleagues proposed that rhythm perception is mediated by the conjunction of a sensory representation of the auditory input and a motor representation of the body (Todd, 1994a, 1995), and that a sense of motion from sound is mediated by the vestibular system (Todd, 1992a, 1993b). These ideas were developed into a sensory-motor theory of rhythm and beat induction (Todd et al., 1999). A neurological substrate was proposed which might form the biological basis of the theory (Todd et al., 2002). The theory was implemented as a computational model and a number of experiments conducted to test it. In the following time there have been several key developments. One is the demonstration that the vestibular system is primal to rhythm perception, and in related work several experiments have provided further evidence that rhythm perception is body dependent. Another is independent advances in imaging, which have revealed the brain areas associated with both vestibular processing and rhythm perception. A third is the finding that vestibular receptors contribute to auditory evoked potentials (Todd et al., 2014a,b). These behavioral and neurobiological developments demand a theoretical overview which could provide a new synthesis over the domain of rhythm perception. In this paper we suggest four propositions as the basis for such a synthesis. (1) Rhythm perception is a form of vestibular perception; (2) Rhythm perception evokes both external and internal guidance of somatotopic representations; (3) A link from the limbic system to the internal guidance pathway mediates the “dance habit”; (4) The vestibular reward mechanism is innate. The new synthesis provides an explanation for a number of phenomena not often considered by rhythm researchers. We discuss these along with possible computational implementations and alternative models and propose a number of new directions for future research. PMID:26379522

  1. Induction of Long-term Depression-like Plasticity by Pairings of Motor Imagination and Peripheral Electrical Stimulation

    PubMed Central

    Jochumsen, Mads; Signal, Nada; Nedergaard, Rasmus W.; Taylor, Denise; Haavik, Heidi; Niazi, Imran K.

    2015-01-01

    Long-term depression (LTD) and long-term potentiation (LTP)-like plasticity are models of synaptic plasticity which have been associated with memory and learning. The induction of LTD and LTP-like plasticity, using different stimulation protocols, has been proposed as a means of addressing abnormalities in cortical excitability associated with conditions such as focal hand dystonia and stroke. The aim of this study was to investigate whether the excitability of the cortical projections to the tibialis anterior (TA) muscle could be decreased when dorsiflexion of the ankle joint was imagined and paired with peripheral electrical stimulation (ES) of the nerve supplying the antagonist soleus muscle. The effect of stimulus timing was evaluated by comparing paired stimulation timed to reach the cortex before, at and after the onset of imagined movement. Fourteen healthy subjects participated in six experimental sessions held on non-consecutive days. The timing of stimulation delivery was determined offline based on the contingent negative variation (CNV) of electroencephalography brain data obtained during imagined dorsiflexion. Afferent stimulation was provided via a single pulse ES to the peripheral nerve paired, based on the CNV, with motor imagination of ankle dorsiflexion. A significant decrease (P = 0.001) in the excitability of the cortical projection of TA was observed when the afferent volley from the ES of the tibial nerve (TN) reached the cortex at the onset of motor imagination based on the CNV. When TN stimulation was delivered before (P = 0.62), or after (P = 0.23) imagined movement onset there was no significant effect. Nor was a significant effect found when ES of the TN was applied independent of imagined movement (P = 0.45). Therefore, the excitability of the cortical projection to a muscle can be inhibited when ES of the nerve supplying the antagonist muscle is precisely paired with the onset of imagined movement. PMID:26648859

  2. Vacuum coupling of rotating superconducting rotor

    DOEpatents

    Shoykhet, Boris A.; Zhang, Burt Xudong; Driscoll, David Infante

    2003-12-02

    A rotating coupling allows a vacuum chamber in the rotor of a superconducting electric motor to be continually pumped out. The coupling consists of at least two concentric portions, one of which is allowed to rotate and the other of which is stationary. The coupling is located on the non-drive end of the rotor and is connected to a coolant supply and a vacuum pump. The coupling is smaller in diameter than the shaft of the rotor so that the shaft can be increased in diameter without having to increase the size of the vacuum seal.

  3. Nonlinear Control of the Doubly Fed Induction Motor with Copper Losses Minimization for Electrical Vehicle

    NASA Astrophysics Data System (ADS)

    Drid, S.; Nait-Said, M.-S.; Tadjine, M.; Makouf, A.

    2008-06-01

    There is an increasing interest in electric vehicles due to environmental concerns. Recent efforts are directed toward developing an improved propulsion system for electric vehicles applications with minimal power losses. This paper deals with the high efficient vector control for the reduction of copper losses of the doubly fed motor. Firstly, the feedback linearization control based on Lyapunov approach is employed to design the underlying controller achieving the double fluxes orientation. The fluxes controllers are designed independently of the speed. The speed controller is designed using the Lyapunov method especially employed to the unknown load torques. The global asymptotic stability of the overall system is theoretically proven. Secondly, a new Torque Copper Losses Factor is proposed to deal with the problem of the machine copper losses. Its main function is to optimize the torque in keeping the machine saturation at an acceptable level. This leads to a reduction in machine currents and therefore their accompanied copper losses guaranteeing improved machine efficiency. The simulation results in comparative presentation confirm largely the effectiveness of the proposed DFIM control with a very interesting energy saving contribution.

  4. Advanced Motors

    SciTech Connect

    Knoth, Edward A; Chelluri, Bhanumathi; Schumaker, Edward J

    2012-12-14

    vProject Summary Transportation energy usage is predicted to increase substantially by 2020. Hybrid vehicles and fuel cell powered vehicles are destined to become more prominent as fuel prices rise with the demand. Hybrid and fuel cell vehicle platforms are both dependent on high performance electric motors. Electric motors for transportation duty will require sizeable low-speed torque to accelerate the vehicle. As motor speed increases, the torque requirement decreases which results in a nearly constant power motor output. Interior permanent magnet synchronous motors (IPMSM) are well suited for this duty. , , These rotor geometries are configured in straight lines and semi circular arc shapes. These designs are of limited configurations because of the lack of availability of permanent magnets of any other shapes at present. We propose to fabricate rotors via a novel processing approach where we start with magnet powders and compact them into a net shape rotor in a single step. Using this approach, widely different rotor designs can be implemented for efficiency. The current limitation on magnet shape and thickness will be eliminated. This is accomplished by co-filling magnet and soft iron powders at specified locations in intricate shapes using specially designed dies and automatic powder filling station. The process fundamentals for accomplishing occurred under a previous Applied Technology Program titled, Motors and Generators for the 21st Century. New efficient motor designs that are not currently possible (or cost prohibitive) can be accomplished by this approach. Such an approach to motor fabrication opens up a new dimension in motor design. Feasibility Results We were able to optimize a IPMSM rotor to take advantage of the powder co-filling and DMC compaction processing methods. The minimum low speed torque requirement of 5 N-m can be met through an optimized design with magnet material having a Br capability of 0.2 T. This level of magnetic performance can

  5. Transient tracking of low and high-order eccentricity-related components in induction motors via TFD tools

    NASA Astrophysics Data System (ADS)

    Climente-Alarcon, V.; Antonino-Daviu, J.; Riera-Guasp, M.; Pons-Llinares, J.; Roger-Folch, J.; Jover-Rodriguez, P.; Arkkio, A.

    2011-02-01

    The present work is focused on the diagnosis of mixed eccentricity faults in induction motors via the study of currents demanded by the machine. Unlike traditional methods, based on the analysis of stationary currents (Motor Current Signature Analysis (MCSA)), this work provides new findings regarding the diagnosis approach proposed by the authors in recent years, which is mainly focused on the fault diagnosis based on the analysis of transient quantities, such as startup or plug stopping currents (Transient Motor Current Signature Analysis (TMCSA)), using suitable time-frequency decomposition (TFD) tools. The main novelty of this work is to prove the usefulness of tracking the transient evolution of high-order eccentricity-related harmonics in order to diagnose the condition of the machine, complementing the information obtained with the low-order components, whose transient evolution was well characterised in previous works. Tracking of high-order eccentricity-related harmonics during the transient, through their associated patterns in the time-frequency plane, may significantly increase the reliability of the diagnosis, since the set of fault-related patterns arising after application of the corresponding TFD tool is very unlikely to be caused by other faults or phenomena. Although there are different TFD tools which could be suitable for the transient extraction of these harmonics, this paper makes use of a Wigner-Ville distribution (WVD)-based algorithm in order to carry out the time-frequency decomposition of the startup current signal, since this is a tool showing an excellent trade-off between frequency resolution at both high and low frequencies. Several simulation results obtained with a finite element-based model and experimental results show the validity of this fault diagnosis approach under several faulty and operating conditions. Also, additional signals corresponding to the coexistence of the eccentricity and other non-fault related phenomena making

  6. An Adaptive Supervisory Sliding Fuzzy Cerebellar Model Articulation Controller for Sensorless Vector-Controlled Induction Motor Drive Systems

    PubMed Central

    Wang, Shun-Yuan; Tseng, Chwan-Lu; Lin, Shou-Chuang; Chiu, Chun-Jung; Chou, Jen-Hsiang

    2015-01-01

    This paper presents the implementation of an adaptive supervisory sliding fuzzy cerebellar model articulation controller (FCMAC) in the speed sensorless vector control of an induction motor (IM) drive system. The proposed adaptive supervisory sliding FCMAC comprised a supervisory controller, integral sliding surface, and an adaptive FCMAC. The integral sliding surface was employed to eliminate steady-state errors and enhance the responsiveness of the system. The adaptive FCMAC incorporated an FCMAC with a compensating controller to perform a desired control action. The proposed controller was derived using the Lyapunov approach, which guarantees learning-error convergence. The implementation of three intelligent control schemes—the adaptive supervisory sliding FCMAC, adaptive sliding FCMAC, and adaptive sliding CMAC—were experimentally investigated under various conditions in a realistic sensorless vector-controlled IM drive system. The root mean square error (RMSE) was used as a performance index to evaluate the experimental results of each control scheme. The analysis results indicated that the proposed adaptive supervisory sliding FCMAC substantially improved the system performance compared with the other control schemes. PMID:25815450

  7. Induction motors airgap-eccentricity detection through the discrete wavelet transform of the apparent power signal under non-stationary operating conditions.

    PubMed

    Yahia, K; Cardoso, A J M; Ghoggal, A; Zouzou, S E

    2014-03-01

    Fast Fourier transform (FFT) analysis has been successfully used for fault diagnosis in induction machines. However, this method does not always provide good results for the cases of load torque, speed and voltages variation, leading to a variation of the motor-slip and the consequent FFT problems that appear due to the non-stationary nature of the involved signals. In this paper, the discrete wavelet transform (DWT) of the apparent-power signal for the airgap-eccentricity fault detection in three-phase induction motors is presented in order to overcome the above FFT problems. The proposed method is based on the decomposition of the apparent-power signal from which wavelet approximation and detail coefficients are extracted. The energy evaluation of a known bandwidth permits to define a fault severity factor (FSF). Simulation as well as experimental results are provided to illustrate the effectiveness and accuracy of the proposed method presented even for the case of load torque variations.

  8. Utilization of rotor kinetic energy storage for hybrid vehicles

    SciTech Connect

    Hsu, John S.

    2011-05-03

    A power system for a motor vehicle having an internal combustion engine, the power system comprises an electric machine (12) further comprising a first excitation source (47), a permanent magnet rotor (28) and a magnetic coupling rotor (26) spaced from the permanent magnet rotor and at least one second excitation source (43), the magnetic coupling rotor (26) also including a flywheel having an inertial mass to store kinetic energy during an initial acceleration to an operating speed; and wherein the first excitation source is electrically connected to the second excitation source for power cycling such that the flywheel rotor (26) exerts torque on the permanent magnet rotor (28) to assist braking and acceleration of the permanent magnet rotor (28) and consequently, the vehicle. An axial gap machine and a radial gap machine are disclosed and methods of the invention are also disclosed.

  9. Motor for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Roopnarine (Inventor)

    2013-01-01

    A high temperature motor has a stator with poles formed by wire windings, and a rotor with magnetic poles on a rotor shaft positioned coaxially within the stator. The stator and rotor are built up from stacks of magnetic-alloy laminations. The stator windings are made of high temperature magnet wire insulated with a vitreous enamel film, and the wire windings are bonded together with ceramic binder. A thin-walled cylinder is positioned coaxially between the rotor and the stator to prevent debris from the stator windings from reaching the rotor. The stator windings are wound on wire spools made of ceramic, thereby avoiding need for mica insulation and epoxy/adhesive. The stator and rotor are encased in a stator housing with rear and front end caps, and rear and front bearings for the rotor shaft are mounted on external sides of the end caps to keep debris from the motor migrating into the bearings' races.

  10. Experimental implementation of a robust damped-oscillation control algorithm on a full-sized, two-degree-of-freedom, AC induction motor-driven crane

    SciTech Connect

    Kress, R.L.; Jansen, J.F.; Noakes, M.W.

    1994-05-01

    When suspended payloads are moved with an overhead crane, pendulum like oscillations are naturally introduced. This presents a problem any time a crane is used, especially when expensive and/or delicate objects are moved, when moving in a cluttered an or hazardous environment, and when objects are to be placed in tight locations. Damped-oscillation control algorithms have been demonstrated over the past several years for laboratory-scale robotic systems on dc motor-driven overhead cranes. Most overhead cranes presently in use in industry are driven by ac induction motors; consequently, Oak Ridge National Laboratory has implemented damped-oscillation crane control on one of its existing facility ac induction motor-driven overhead cranes. The purpose of this test was to determine feasibility, to work out control and interfacing specifications, and to establish the capability of newly available ac motor control hardware with respect to use in damped-oscillation-controlled systems. Flux vector inverter drives are used to investigate their acceptability for damped-oscillation crane control. The purpose of this paper is to describe the experimental implementation of a control algorithm on a full-sized, two-degree-of-freedom, industrial crane; describe the experimental evaluation of the controller including robustness to payload length changes; explain the results of experiments designed to determine the hardware required for implementation of the control algorithms; and to provide a theoretical description of the controller.

  11. Hybrid vehicle motor alignment

    DOEpatents

    Levin, Michael Benjamin

    2001-07-03

    A rotor of an electric motor for a motor vehicle is aligned to an axis of rotation for a crankshaft of an internal combustion engine having an internal combustion engine and an electric motor. A locator is provided on the crankshaft, a piloting tool is located radially by the first locator to the crankshaft. A stator of the electric motor is aligned to a second locator provided on the piloting tool. The stator is secured to the engine block. The rotor is aligned to the crankshaft and secured thereto.

  12. Process Improvements for the AH-64 Tail Rotor Vibration Analysis

    DTIC Science & Technology

    2007-06-01

    Free vortex wake (Scully) ! 7. Wind turbine induction flow (rotors only) a 1...Scissor Tail Rotor Variant 7 Figure 4. RPM Sensor Installation (17) 12 Figure 5. Accelerometer and Tachometer Installation locations. (17) 13 Figure...weight adjusted made to the aft pocket. (17) An accelerometer is used to measure the accelerations in vertical direction. An optical tachometer is

  13. Making a Simple Self-Starting Electric Motor

    ERIC Educational Resources Information Center

    Hong, Seok-In; Choi, Jung-In; Hong, Seok-Cheol

    2009-01-01

    A simple electric motor has a problem in that the current applied to the motor per se can rarely trigger its rotation. Usually such motors begin to rotate after the rotor is slightly turned by hand (i.e., manual starting). In a "self-starting" motor, the rotor starts to rotate spontaneously as soon as the current is applied. This paper describes…

  14. Extended cage adjustable speed electric motors and drive packages

    DOEpatents

    Hsu, J.S.

    1999-03-23

    The rotor cage of a motor is extended, a second stator is coupled to this extended rotor cage, and the windings have the same number of poles. The motor torque and speed can be controlled by either injecting energy into or extracting energy out from the rotor cage. The motor produces less harmonics than existing doubly-fed motors. Consequently, a new type of low cost, high efficiency drive is produced. 12 figs.

  15. Extended cage adjustable speed electric motors and drive packages

    DOEpatents

    Hsu, John S.

    1999-01-01

    The rotor cage of a motor is extended, a second stator is coupled to this extended rotor cage, and the windings have the same number of poles. The motor torque and speed can be controlled by either injecting energy into or extracting energy out from the rotor cage. The motor produces less harmonics than existing doubly-fed motors. Consequently, a new type of low cost, high efficiency drive is produced.

  16. Flywheel system using wire-wound rotor

    DOEpatents

    Chiao, Edward Young; Bender, Donald Arthur; Means, Andrew E.; Snyder, Philip K.

    2016-06-07

    A flywheel is described having a rotor constructed of wire wound onto a central form. The wire is prestressed, thus mitigating stresses that occur during operation. In another aspect, the flywheel incorporates a low-loss motor using electrically non-conducting permanent magnets.

  17. Brushless direct-current motor with stationary armature and field

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1970-01-01

    Electronically commutated dc motor has an active fixed field winding, and active fixed armature winding, and passive rotor. By use of brushless dc motor switching technique, motor provides continuous controllable and reversible torque without use of sliding contacts.

  18. Open Rotor Development

    NASA Technical Reports Server (NTRS)

    Van Zante, Dale E.; Rizzi, Stephen A.

    2016-01-01

    The ERA project executed a comprehensive test program for Open Rotor aerodynamic and acoustic performance. System studies used the data to estimate the fuel burn savings and acoustic margin for an aircraft system with open rotor propulsion. The acoustic measurements were used to produce an auralization that compares the legacy blades to the current generation of open rotor designs.

  19. A 2D magnetic and 3D mechanical coupled finite element model for the study of the dynamic vibrations in the stator of induction motors

    NASA Astrophysics Data System (ADS)

    Martinez, J.; Belahcen, A.; Detoni, J. G.

    2016-01-01

    This paper presents a coupled Finite Element Model in order to study the vibrations in induction motors under steady-state. The model utilizes a weak coupling strategy between both magnetic and elastodynamic fields on the structure. Firstly, the problem solves the magnetic vector potential in an axial cut and secondly the former solution is coupled to a three dimensional model of the stator. The coupling is performed using projection based algorithms between the computed magnetic solution and the three-dimensional mesh. The three-dimensional model of the stator includes both end-windings and end-shields in order to give a realistic picture of the motor. The present model is validated using two steps. Firstly, a modal analysis hammer test is used to validate the material characteristic of this complex structure and secondly an array of accelerometer sensors is used in order to study the rotating waves using multi-dimensional spectral techniques. The analysis of the radial vibrations presented in this paper firstly concludes that slot harmonic components are visible when the motor is loaded. Secondly, the multidimensional spectrum presents the most relevant mechanical waves on the stator such as the ones produced by the space harmonics or the saturation of the iron core. The direct retrieval of the wave-number in a multi-dimensional spectrum is able to show the internal current distribution in a non-intrusive way. Experimental results for healthy induction motors are showing mechanical imbalances in a multi-dimensional spectrum in a more straightforward form.

  20. Computational Study of Flow Interactions in Coaxial Rotors

    NASA Technical Reports Server (NTRS)

    Yoon, Seokkwan; Lee, Henry C.; Pulliam, Thomas H.

    2016-01-01

    Although the first idea of coaxial rotors appeared more than 150 years ago, most helicopters have used single main-rotor/tail-rotor combination. Since reactive moments of coaxial rotors are canceled by contra-rotation, no tail rotor is required to counter the torque generated by the main rotor. Unlike the single main rotor design that distributes power to both main and tail rotors, all of the power for coaxial rotors is used for vertical thrust. Thus, no power is wasted for anti-torque or directional control. The saved power helps coaxial rotors reach a higher hover ceiling than single rotor helicopters. Another advantage of coaxial rotors is that the overall rotor diameter can be reduced for a given vehicle gross weight because each rotor provides a maximum contribution to vertical thrust to overcome vehicle weight. However, increased mechanical complexity of the hub has been one of the challenges for manufacturing coaxial rotorcraft. Only the Kamov Design Bureau of Russia had been notably successful in production of coaxial helicopters until Sikorsky built X2, an experimental compound helicopter. Recent developments in unmanned aircraft systems and high-speed rotorcraft have renewed interest in the coaxial configuration. Multi-rotors are frequently used for small electric unmanned rotorcraft partly due to mechanical simplicity. The use of multiple motors provides redundancy as well as cost-efficiency. The multi-rotor concept has rarely been used until recently because of its inherent stability and control problems. However, advances in inexpensive electronic flight control systems have opened the floodgates for small drones using multirotors. Coaxial rotors have started to appear in some multi-rotor configurations. Small coaxial rotors have often been designed using a hundred year old approach that is "sketch, build, fly, and iterate." In that approach, there is no systematic way to explore trade-offs or determine logical next steps. It is neither possible to

  1. Broken rotor bars detection by a new non-invasive diagnostic procedure

    NASA Astrophysics Data System (ADS)

    Eltabach, Mario; Antoni, Jerome; Shanina, Galyna; Sieg-Zieba, Sophie; Carniel, Xavier

    2009-05-01

    A new technique of diagnosing data for broken rotor bars in induction motors derived from two of the three stator currents, the Beirut diagnostic procedure (BDP) is presented in this paper. The theoretical principles directly related to the application of this diagnostic technique are described, emphasizing the use of a severity factor in order to evaluate the extension of the fault. Defining the severity factor as the normalized amplitude of the fault characteristic frequency enables us to draw up a table of comparison of several usual electric diagnostic methods. Besides the traditional one-phase current spectrum analysis, values of the severity factor related to electrical signals like the instantaneous powers, the current space vector modulus and finally related to the new Beirut diagnostic method are analyzed with respect to the variation of the power factor angle and of the sum of the two current side-band angular displacement. The BDP offers several advantages over the usual motor current signature analyses (MCSA) methods: it is shown how the proposed severity factor applied to the new diagnostic technique is not dependent on motor parameters such as the power factor angle and the fault type which is not the case of the instantaneous powers. In addition, the BDP has the advantage of detecting easily fault characteristic frequencies, which is not possible via diagnostic methods that use the detection of two side-band components as in the simple current spectrum. By theoretical analysis, computer simulations, and laboratory experiments, it is shown that the new method enhances the reliability of diagnostics of broken rotor bars in induction motor.

  2. Hermetically sealed superconducting magnet motor

    DOEpatents

    DeVault, R.C.; McConnell, B.W.; Phillips, B.A.

    1996-07-02

    A hermetically sealed superconducting magnet motor includes a rotor separated from a stator by either a radial gap, an axial gap, or a combined axial and radial gap. Dual conically shaped stators are used in one embodiment to levitate a disc-shaped rotor made of superconducting material within a conduit for moving cryogenic fluid. As the rotor is caused to rotate when the field stator is energized, the fluid is pumped through the conduit. 6 figs.

  3. Hermetically sealed superconducting magnet motor

    DOEpatents

    DeVault, Robert C.; McConnell, Benjamin W.; Phillips, Benjamin A.

    1996-01-01

    A hermetically sealed superconducting magnet motor includes a rotor separated from a stator by either a radial gap, an axial gap, or a combined axial and radial gap. Dual conically shaped stators are used in one embodiment to levitate a disc-shaped rotor made of superconducting material within a conduit for moving cryogenic fluid. As the rotor is caused to rotate when the field stator is energized, the fluid is pumped through the conduit.

  4. Molecular Rotors Built in Porous Materials.

    PubMed

    Comotti, Angiolina; Bracco, Silvia; Sozzani, Piero

    2016-09-20

    Molecules and materials can show dynamic structures in which the dominant mechanism is rotary motion. The single mobile elements are defined as "molecular rotors" and exhibit special properties (compared with their static counterparts), being able in perspective to greatly modulate the dielectric response and form the basis for molecular motors that are designed with the idea of making molecules perform a useful mechanical function. The construction of ordered rotary elements into a solid is a necessary feature for such design, because it enables the alignment of rotors and the fine-tuning of their steric and dipolar interactions. Crystal surfaces or bulk crystals are the most suitable to adapt rotors in 2D or 3D arrangements and engineer juxtaposition of the rotors in an ordered way. Nevertheless, it is only in recent times that materials showing porosity and remarkably low density have undergone tremendous development. The characteristics of large free volume combine well with the virtually unhindered motion of the molecular rotors built into their structure. Indeed, the molecular rotors are used as struts in porous covalent and supramolecular architectures, spanning both hybrid and fully organic materials. The modularity of the approach renders possible a variety of rotor geometrical arrangements in both robust frameworks stable up to 850 K and self-assembled molecular materials. A nanosecond (fast dynamics) motional regime can be achieved at temperatures lower than 240 K, enabling rotor arrays operating in the solid state even at low temperatures. Furthermore, in nanoporous materials, molecular rotors can interact with the diffusing chemical species, be they liquids, vapors, or gases. Through this chemical intervention, rotor speed can be modulated at will, enabling a new generation of rotor-containing materials sensitive to guests. In principle, an applied electric field can be the stimulus for chemical release from porous materials. The effort needed to

  5. Trapped field internal dipole superconducting motor generator

    DOEpatents

    Hull, John R.

    2001-01-01

    A motor generator including a high temperature superconductor rotor and an internally disposed coil assembly. The motor generator superconductor rotor is constructed of a plurality of superconductor elements magnetized to produce a dipole field. The coil assembly can be either a conventional conductor or a high temperature superconductor. The superconductor rotor elements include a magnetization direction and c-axis for the crystals of the elements and which is oriented along the magnetization direction.

  6. A Position Sensorless Control Method for SRM Based on Variation of Phase Inductance

    NASA Astrophysics Data System (ADS)

    Komatsuzaki, Akitomo; Miki, Ichiro

    Switched reluctance motor (SRM) drives are suitable for variable speed industrial applications because of the simple structure and high-speed capability. However, it is necessary to detect the rotor position with a position sensor attached to the motor shaft. The use of the sensor increases the cost of the drive system and machine size, and furthermore the reliability of the system is reduced. Therefore, several approaches to eliminate the position sensor have already been reported. In this paper, a position sensorless control method based on the variation of the phase inductance is described. The phase inductance regularly varies with the rotor position. The SRM is controlled without the position sensor using the de-fluxing period and the phase inductance. The turn-off timing is determined by computing the difference of angle between the sampling point and the aligned point and the variation of angle during the de-fluxing period. In the magnetic saturation region, the phase inductance at the current when the effect of the saturation starts is computed and the sensorless control can be carried out using this inductance. Experimental results show that the SRM is well controlled without the position sensor using the proposed method.

  7. Reactor coolant pump testing using motor current signatures analysis

    SciTech Connect

    Burstein, N.; Bellamy, J.

    1996-12-01

    This paper describes reactor coolant pump motor testing carried out at Florida Power Corporation`s Crystal River plant using Framatome Technologies` new EMPATH (Electric Motor Performance Analysis and Trending Hardware) system. EMPATH{trademark} uses an improved form of Motor Current Signature Analysis (MCSA), technology, originally developed at Oak Ridge National Laboratories, for detecting deterioration in the rotors of AC induction motors. Motor Current Signature Analysis (MCSA) is a monitoring tool for motor driven equipment that provides a non-intrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment. The base technology was developed at the Oak Ridge National Laboratory as a means for determining the affects of aging and service wear specifically on motor-operated valves used in nuclear power plant safety systems, but it is applicable to a broad range of electric machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. The motor current variations, resulting from changes in load caused by gears, pulleys, friction, bearings, and other conditions that may change over the life of the motor, are carried by the electrical cables powering the motor and are extracted at any convenient location along the motor lead. These variations modulate the 60 Hz carrier frequency and appear as sidebands in the spectral plot.

  8. Ultra-Efficient and Power Dense Electric Motors for U. S. Industry

    SciTech Connect

    Melfi, Michael J.; Schiferl, Richard F.; Umans, Stephen D.

    2013-03-12

    The primary purpose of this project was to combine the ease-of-installation and ease-of-use attributes of industrial induction motors with the low-loss and small size and weight advantages of PM motors to create an ultra-efficient, high power density industrial motor that can be started across-the-line or operated from a standard, Volts/Hertz drive without the need for a rotor position feedback device. PM motor products that are currently available are largely variable speed motors that require a special adjustable speed drive with rotor position feedback. The reduced size and weight helps to offset the magnet cost in order make these motors commercially viable. The scope of this project covers horsepower ratings from 20 ? 500. Prototypes were built and tested at ratings ranging from 30 to 250 HP. Since fans, pumps and compressors make up a large portion of industrial motor applications, the motor characteristics are tailored to those applications. Also, since there is extensive use of adjustable frequency inverters in these applications, there is the opportunity to design for an optimal pole number and operate at other than 60 Hz frequency when inverters are utilized. Designs with four and eight pole configurations were prototyped as part of this work. Four pole motors are the most commonly used configuration in induction motors today. The results of the prototype design, fabrication, and testing were quite successful. The 50 HP rating met all of the design goals including efficiency and power density. Tested values of motor losses at 50 HP were 30% lower than energy efficient induction motors and the motor weight is 35% lower than the energy efficient induction motor of the same rating. Further, when tested at the 30 HP rating that is normally built in this 286T frame size, the efficiency far exceeds the project design goals with 30 HP efficiency levels indicating a 55% reduction in loss compared to energy efficient motors with a motor weight that is a few

  9. Blade-Pitch Control for Quieting Tilt-Rotor Aircraft

    NASA Technical Reports Server (NTRS)

    Betzina, Mark D.; Nguyen, Khanh Q.

    2004-01-01

    A method of reducing the noise generated by a tilt-rotor aircraft during descent involves active control of the blade pitch of the rotors. This method is related to prior such noise-reduction methods, of a type denoted generally as higher-harmonic control (HHC), in which the blade pitch is made to oscillate at a harmonic of the frequency of rotation of the rotor. A tilt-rotor aircraft is so named because mounted at its wing tips are motors that can be pivoted to enable the aircraft to take off and land like a helicopter or to fly like a propeller airplane. When the aircraft is operating in its helicopter mode, the rotors generate more thrust per unit rotor-disk area than helicopter rotors do, thus producing more blade-vortex interaction (BVI) noise. BVI is a major source of noise produced by helicopters and tilt-rotor aircraft during descent: When a rotor descends into its own wake, the interaction of each blade with the blade-tip vortices generated previously gives rise to large air-pressure fluctuations. These pressure fluctuations radiate as distinct, impulsive noise. In general, the pitch angle of the rotor blades of a tilt-rotor aircraft is controlled by use of a swash plate connected to the rotor blades by pitch links. In both prior HHC methods and the present method, HHC control signals are fed as input to swash-plate control actuators, causing the rotor-blade pitch to oscillate. The amplitude, frequency, and phase of the control signal can be chosen to minimize BVI noise.

  10. Condition monitoring of gearboxes using synchronously averaged electric motor signals

    NASA Astrophysics Data System (ADS)

    Ottewill, J. R.; Orkisz, M.

    2013-07-01

    Due to their prevalence in rotating machinery, the condition monitoring of gearboxes is extremely important in the minimization of potentially dangerous and expensive failures. Traditionally, gearbox condition monitoring has been conducted using measurements obtained from casing-mounted vibration transducers such as accelerometers. A well-established technique for analyzing such signals is the synchronous signal average, where vibration signals are synchronized to a measured angular position and then averaged from rotation to rotation. Driven, in part, by improvements in control methodologies based upon methods of estimating rotor speed and torque, induction machines are used increasingly in industry to drive rotating machinery. As a result, attempts have been made to diagnose defects using measured terminal currents and voltages. In this paper, the application of the synchronous signal averaging methodology to electric drive signals, by synchronizing stator current signals with a shaft position estimated from current and voltage measurements is proposed. Initially, a test-rig is introduced based on an induction motor driving a two-stage reduction gearbox which is loaded by a DC motor. It is shown that a defect seeded into the gearbox may be located using signals acquired from casing-mounted accelerometers and shaft mounted encoders. Using simple models of an induction motor and a gearbox, it is shown that it should be possible to observe gearbox defects in the measured stator current signal. A robust method of extracting the average speed of a machine from the current frequency spectrum, based on the location of sidebands of the power supply frequency due to rotor eccentricity, is presented. The synchronous signal averaging method is applied to the resulting estimations of rotor position and torsional vibration. Experimental results show that the method is extremely adept at locating gear tooth defects. Further results, considering different loads and different

  11. Augmented motor activity and reduced striatal preprodynorphin mRNA induction in response to acute amphetamine administration in metabotropic glutamate receptor 1 knockout mice.

    PubMed

    Mao, L; Conquet, F; Wang, J Q

    2001-01-01

    Metabotropic glutamate receptor 1 (mGluR1) is a G-protein-coupled receptor and is expressed in the medium spiny projection neurons of mouse striatum. To define the role of mGluR1 in actions of psychostimulant, we compared both motor behavior and striatal neuropeptide mRNA expression between mGluR1 mutant and wild-type control mice after a single injection of amphetamine. We found that acute amphetamine injection increased motor activity in both mutant and control mice in a dose-dependent manner (1, 4, and 12 mg/kg, i.p.). However, the overall motor responses of mGluR1 -/- mice to all three doses of amphetamine were significantly greater than those of wild-type +/+ mice. Amphetamine also induced a dose-dependent elevation of preprodynorphin mRNA in the dorsal and ventral striatum of mutant and wild-type mice as revealed by quantitative in situ hybridization. In contrast to behavioral responses, the induction of dynorphin mRNA in both the dorsal and ventral striatum of mutant mice was significantly less than that of wild-type mice in response to the two higher doses of amphetamine. In addition, amphetamine elevated basal levels of substance P mRNA in the dorsal and ventral striatum of mGluR1 mutant mice to a similar level as that of wild-type mice. There were no differences in basal levels and distribution patterns of the two mRNAs between the two genotypes of mice treated with saline. These results demonstrate a clear augmented behavioral response of mGluR1 knockout mice to acute amphetamine exposure that is closely correlated with reduced dynorphin mRNA induction in the same mice. It appears that an intact mGluR1 is specifically critical for full dynorphin induction, and impaired mobilization of inhibitory dynorphin system as a result of lacking mGluR1 may contribute to an augmentation of motor stimulation in response to acute administration of psychostimulant.

  12. Improved Bearingless Switched-Reluctance Motor

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.

    2003-01-01

    The Morrison rotor, named after its inventor, is a hybrid rotor for use in a bearingless switched-reluctance electric motor. The motor is characterized as bearingless in the sense that it does not rely on conventional mechanical bearings: instead, it functions as both a magnetic bearing and a motor. Bearingless switched-reluctance motors are attractive for use in situations in which large variations in temperatures and/or other extreme conditions preclude the use of conventional electric motors and mechanical bearings. In the Morrison motor, as in a prior bearingless switched-reluctance motor, a multipole rotor is simultaneously levitated and rotated. In the prior motor, simultaneous levitation and rotation are achieved by means of two kinds of stator windings: (1) main motor windings and (2) windings that exert levitating forces on a multipole rotor. The multipole geometry is suboptimum for levitation in that it presents a discontinuous surface to the stator pole faces, thereby degrading the vibration-suppression capability of the magnetic bearing. The Morrison rotor simplifies the stator design in that the stator contains only one type of winding. The rotor is a hybrid that includes both (1) a circular lamination stack for levitation and (2) a multipole lamination stack for rotation. A prototype includes six rotor poles and eight stator poles (see figure). During normal operation, two of the four pairs of opposing stator poles (each pair at right angles to the other pair) levitate the rotor. The remaining two pairs of stator poles exert torque on the six-pole rotor lamination stack to produce rotation. The relative lengths of the circular and multipole lamination stacks on the rotor can be chosen to tailor the performance of the motor for a specific application. For a given overall length, increasing the length of the multipole stack relative to the circular stack results in an increase in torque relative to levitation load capacity and stiffness, and vice versa.

  13. Bearingless Switched-Reluctance Motor Improved

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.

    2004-01-01

    The Morrison rotor, named after its inventor, is a hybrid rotor for use in a switched reluctance electric motor. The motor is characterized as bearingless in the sense that it does not rely on conventional mechanical bearings: instead, it functions as both a magnetic bearing and a motor. Bearingless switched-reluctance motors are attractive for use in situations in which large variations in temperatures and/or other extreme conditions preclude the use of conventional electric motors and mechanical bearings. In the Morrison motor, as in prior bearingless switched-reluctance motors, a multipole rotor is simultaneously levitated and rotated. In the prior motors, simultaneous levitation and rotation are achieved by means of two kinds of stator windings: (1) main motor windings and (2) windings that exert levitating forces on a multipole rotor. The multipole geometry is suboptimum for levitation because it presents a discontinuous surface to the stator pole faces, thereby degrading the vibration suppression capability of the magnetic bearing. The Morrison rotor simplifies the stator design in that it contains only one type of winding. The rotor is a hybrid that includes both (1) a circular lamination stack for levitation and (2) a multipole lamination stack for rotation. Simultaneous levitation and rotation at 6000 rpm were achieved with a prototype that included six rotor poles and eight stator poles. During normal operation, two of the four pairs of opposing stator poles (each pair at right angles to the other pair) levitate the rotor. The remaining two pairs of stator poles exert torque on the six-pole rotor lamination stack to produce rotation. The relative length of the circular and multipole lamination stacks on the rotor can be chosen to tailor the performance of the motor for a specific application. For a given overall length, increasing the length of the multipole stack relative to the circular stack results in an increase in torque relative to the levitation

  14. Direct drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1998-03-10

    A positive-drive field actuator motor is described which includes a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 62 figs.

  15. Meissner-Effect Stepping Motor

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A.

    1991-01-01

    Proposed stepping motor derives torque from diamagnetic repulsion produced by Meissner effect - exclusion of magnetic field from interior of superconductor. Design of motor takes advantage of silver-doped YB2Cu3O and other compounds superconductive at temperatures as high as that of liquid nitrogen. Skin of rotor cooled below its superconducting-transition temperature by liquid nitrogen. O-rings prevent leaks of liquid nitrogen from rotor. Weight, cost, and maintenance reduced.

  16. Direct drive field actuator motors

    SciTech Connect

    Grahn, Allen R.

    1998-01-01

    A positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  17. Fractional-Slot Surface Mounted PM Motors with Concentrated Windings for HEV Traction Drives

    SciTech Connect

    Bailey, J.M.

    2005-10-24

    High-power density and efficiency resulting from elimination of rotor windings and reduced magnetic-flux losses have made the rare earth permanent magnet (PM) motor a leading candidate for the Department of Energy's Office of FreedomCAR and Vehicle Technologies (FCVTs) traction drive motor. These traction drives are generally powered by radial-gap motors, having the magnets on or embedded in a rotating cylinder separated from the inside surface of a slotted cylindrical stator by an annular gap. The two main types of radial-gap PM rotors are those with magnets mounted on the surface of a supporting back iron, called PM surface mounted (PMSM) motors, and those with magnets mounted in slots in the rotor, called interior PM (IPM) motors. Most early PM motor research was on the PMSM motor, which was thought to have an inherently low stator inductance. A low stator inductance can lead to currents dangerously exceeding rated current as the back-emf across the inductance increases with speed; consequently, part of the attempted solution has been to increase the stator inductance to reduce the rate of current rise. Although analysis suggested that there should be no problem designing sufficiently high stator inductance into PMSMs, attempts to do so were often not successful and a motor design was sought that would have a higher intrinsic inductance. Commercial research at Toyota has focused on IPM motors because they can achieve a high-saliency ratio, which helps them operate over a high constant power speed ratio (CPSR), but they are more difficult to fabricate. The Oak Ridge National Laboratory's (ORNL) position has been to continue research on brushless direct current (dc) motors (BDCMs) because of ease of fabrication and increased power output. Recently there has been a revival of interest in a fractional-slot PMSMs [15] made with concentrated windings because they possess three important features. First, they can increase the motor's inductance sufficiently to reduce

  18. Energy efficient motors

    NASA Astrophysics Data System (ADS)

    1995-01-01

    This TechData Sheet is intended to help activity personnel identify cost effective energy projects for energy efficient motors. With this guide an energy manager can identify when an energy efficient induction motor should be used.

  19. Rotor control system

    NASA Technical Reports Server (NTRS)

    Bradford, Michael P. (Inventor); Maciolek, Joseph R. (Inventor)

    1987-01-01

    A helicopter rotor control system (13) including a stop azimuth controller (32) for establishing the value of a deceleration command (15') to a deceleration controller (23), a transition azimuth predictor (41) and a position reference generator (55), which are effective during the last revolution of said rotor (14) to establish a correction indication (38) to adjust the deceleration command (15') to ensure that one of the rotor blades (27) stops at a predetermined angular position.

  20. Electric motor for laser-mechanical drilling

    DOEpatents

    Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

    2015-07-07

    A high power laser drilling system utilizing an electric motor laser bottom hole assembly. A high power laser beam travels within the electric motor for advancing a borehole. High power laser drilling system includes a down hole electrical motor having a hollow rotor for conveying a high power laser beam through the electrical motor.

  1. Control Coil Arrangement for a Rotating Machine Rotor

    SciTech Connect

    Shah, Manoj R.; Lewandowski, Chad R.

    1999-05-05

    A rotating machine (e.g., a turbine, motor or generator) is provided wherein a fixed solenoid or other coil configuration is disposed adjacent to one or both ends of the active portion of the machine rotor for producing an axially directed flux in the active portion so as to provide planar axial control at single or multiple locations for rotor balance, levitation, centering, torque and thrust action. Permanent magnets can be used to produce an axial bias magnetic field. The rotor can include magnetic disks disposed in opposed, facing relation to the coil configuration.

  2. Control coil arrangement for a rotating machine rotor

    DOEpatents

    Shah, Manoj R.; Lewandowsk, Chad R.

    2001-07-31

    A rotating machine (e.g., a turbine, motor or generator) is provided wherein a fixed solenoid or other coil configuration is disposed adjacent to one or both ends of the active portion of the machine rotor for producing an axially directed flux in the active portion so as to provide planar axial control at single or multiple locations for rotor balance, levitation, centering, torque and thrust action. Permanent magnets can be used to produce an axial bias magnetic field. The rotor can include magnetic disks disposed in opposed, facing relation to the coil configuration.

  3. Long-Term Fatigue Life Expenditure of Turbine Shafts Owing to Noncharacteristic Harmonics Produced by Slip Energy Recovery Induction Motor Drives

    NASA Astrophysics Data System (ADS)

    Tsai, Jong-Ian

    In this paper, the long-term effect of noncharacteristic harmonics resulting from a slip energy recovery induction motor drive (SERIMD) on the fatigue life expenditure of turbine-generator shafts is analyzed. A feed-water pump (FP) in power plants is one of the most essential pieces of auxiliary equipment and consumes considerably large quantities of energy. An SERIMD has many advantages and is an adequate candidate for the purpose of variable speed control. However, it gives rise to sustainable variable frequency subharmonics which induce electromechanical subsynchronous oscillations in turbine shafts through proposed deductions. Accordingly, the author has determined that the long-term effect of these subharmonics is a cause of fatigue damage on turbine shafts even under normal operating conditions through fatigue life estimation.

  4. Simulative and experimental investigation on stator winding turn and unbalanced supply voltage fault diagnosis in induction motors using Artificial Neural Networks.

    PubMed

    Lashkari, Negin; Poshtan, Javad; Azgomi, Hamid Fekri

    2015-11-01

    The three-phase shift between line current and phase voltage of induction motors can be used as an efficient fault indicator to detect and locate inter-turn stator short-circuit (ITSC) fault. However, unbalanced supply voltage is one of the contributing factors that inevitably affect stator currents and therefore the three-phase shift. Thus, it is necessary to propose a method that is able to identify whether the unbalance of three currents is caused by ITSC or supply voltage fault. This paper presents a feedforward multilayer-perceptron Neural Network (NN) trained by back propagation, based on monitoring negative sequence voltage and the three-phase shift. The data which are required for training and test NN are generated using simulated model of stator. The experimental results are presented to verify the superior accuracy of the proposed method.

  5. Flexible rotor dynamics analysis

    NASA Technical Reports Server (NTRS)

    Shen, F. A.

    1973-01-01

    A digital computer program was developed to analyze the general nonaxisymmetric and nonsynchronous transient and steady-state rotor dynamic performance of a bending- and shear-wise flexible rotor-bearing system under various operating conditions. The effects of rotor material mechanical hysteresis, rotor torsion flexibility, transverse effects of rotor axial and torsional loading and the anisotropic, in-phase and out-of-phase bearing stiffness and damping force and moment coefficients were included in the program to broaden its capability. An optimum solution method was found and incorporated in the computer program. Computer simulation of experimental data was made and qualitative agreements observed. The mathematical formulations, computer program verification, test data simulation, and user instruction was presented and discussed.

  6. Effect of AFT Rotor on the Inter-Rotor Flow of an Open Rotor Propulsion System

    NASA Technical Reports Server (NTRS)

    Slaboch, Paul E.; Stephens, David B.; Van Zante, Dale E.

    2016-01-01

    The effects of the aft rotor on the inter-rotor flow field of an open rotor propulsion rig were examined. A Particle Image Velocimetry (PIV) dataset that was acquired phase locked to the front rotor position has been phase averaged based on the relative phase angle between the forward and aft rotors. The aft rotor phase was determined by feature tracking in raw PIV images through an image processing algorithm. The effect of the aft rotor potential field on the inter-rotor flow were analyzed and shown to be in good agreement with Computational Fluid Dynamics (CFD) simulations. It was shown that the aft rotor had no substantial effect on the position of the forward rotor tip vortex but did have a small effect on the circulation strength of the vortex when the rotors were highly loaded.

  7. Tilt rotor hover aeroacoustics

    NASA Technical Reports Server (NTRS)

    Coffen, Charles David

    1992-01-01

    The methodology, results, and conclusions of a study of tilt rotor hover aeroacoustics and aerodynamics are presented. Flow visualization and hot wire velocity measurement were performed on a 1/12-scale model of the XV-15 Tilt Rotor Aircraft in hover. The wing and fuselage below the rotor cause a complex recirculating flow. Results indicate the physical dimensions and details of the flow including the relative unsteadiness and turbulence characteristics of the flow. Discrete frequency harmonic thickness and the loading noise mechanism were predicted using WOPWOP for the standard metal blades and the Advanced Technology Blades. The recirculating flow created by the wing below the rotor is a primary sound mechanism for a hovering tilt rotor. The effects of dynamic blade response should be included for fountain flow conditions which produce impulsive blade loading. Broadband noise mechanisms were studied using Amiet's method with azimuthally varying turbulence characteristics derived from the measurements. The recirculating fountain flow with high turbulence levels in the recirculating zone is the dominant source of broadband noise for a hovering rotor. It is shown that tilt rotor hover aeroacoustic noise mechanisms are now understood. Noise predictions can be made based on reasonably accurate aerodynamic models developed here.

  8. Open Rotor Aeroacoustic Modelling

    NASA Technical Reports Server (NTRS)

    Envia, Edmane

    2012-01-01

    Owing to their inherent fuel efficiency, there is renewed interest in developing open rotor propulsion systems that are both efficient and quiet. The major contributor to the overall noise of an open rotor system is the propulsor noise, which is produced as a result of the interaction of the airstream with the counter-rotating blades. As such, robust aeroacoustic prediction methods are an essential ingredient in any approach to designing low-noise open rotor systems. To that end, an effort has been underway at NASA to assess current open rotor noise prediction tools and develop new capabilities. Under this effort, high-fidelity aerodynamic simulations of a benchmark open rotor blade set were carried out and used to make noise predictions via existing NASA open rotor noise prediction codes. The results have been compared with the aerodynamic and acoustic data that were acquired for this benchmark open rotor blade set. The emphasis of this paper is on providing a summary of recent results from a NASA Glenn effort to validate an in-house open noise prediction code called LINPROP which is based on a high-blade-count asymptotic approximation to the Ffowcs-Williams Hawkings Equation. The results suggest that while predicting the absolute levels may be difficult, the noise trends are reasonably well predicted by this approach.

  9. Open Rotor Aeroacoustic Modeling

    NASA Technical Reports Server (NTRS)

    Envia, Edmane

    2012-01-01

    Owing to their inherent fuel efficiency, there is renewed interest in developing open rotor propulsion systems that are both efficient and quiet. The major contributor to the overall noise of an open rotor system is the propulsor noise, which is produced as a result of the interaction of the airstream with the counter-rotating blades. As such, robust aeroacoustic prediction methods are an essential ingredient in any approach to designing low-noise open rotor systems. To that end, an effort has been underway at NASA to assess current open rotor noise prediction tools and develop new capabilities. Under this effort, high-fidelity aerodynamic simulations of a benchmark open rotor blade set were carried out and used to make noise predictions via existing NASA open rotor noise prediction codes. The results have been compared with the aerodynamic and acoustic data that were acquired for this benchmark open rotor blade set. The emphasis of this paper is on providing a summary of recent results from a NASA Glenn effort to validate an in-house open noise prediction code called LINPROP which is based on a high-blade-count asymptotic approximation to the Ffowcs-Williams Hawkings Equation. The results suggest that while predicting the absolute levels may be difficult, the noise trends are reasonably well predicted by this approach.

  10. Propulsion Wheel Motor for an Electric Vehicle

    NASA Technical Reports Server (NTRS)

    Figuered, Joshua M. (Inventor); Herrera, Eduardo (Inventor); Waligora, Thomas M. (Inventor); Bluethmann, William J. (Inventor); Farrell, Logan Christopher (Inventor); Lee, Chunhao J. (Inventor); Vitale, Robert L. (Inventor); Winn, Ross Briant (Inventor); Eggleston, IV, Raymond Edward (Inventor); Guo, Raymond (Inventor); Weber, Steven J. (Inventor); Junkin, Lucien Q. (Inventor); Rogers, James Jonathan (Inventor)

    2016-01-01

    A wheel assembly for an electric vehicle includes a wheel rim that is concentrically disposed about a central axis. A propulsion-braking module is disposed within an interior region of the wheel rim. The propulsion-braking module rotatably supports the wheel rim for rotation about the central axis. The propulsion-braking module includes a liquid cooled electric motor having a rotor rotatable about the central axis, and a stator disposed radially inside the rotor relative to the central axis. A motor-wheel interface hub is fixedly attached to the wheel rim, and is directly attached to the rotor for rotation with the rotor. The motor-wheel interface hub directly transmits torque from the electric motor to the wheel rim at a 1:1 ratio. The propulsion-braking module includes a drum brake system having an electric motor that rotates a cam device, which actuates the brake shoes.

  11. Study of the Synchronous Reluctance Motor Design

    NASA Astrophysics Data System (ADS)

    Dirba, J.; Lavrinovicha, L.; Dobriyan, R.

    2016-08-01

    The paper focuses on studying the external-rotor synchronous reluctance motor. The analysis is performed to estimate the influence of the number of stator slots and non-magnetic areas in the rotor (i.e., flux barriers) on the electromagnetic torque and torque ripple of the studied motor. It is concluded that the increase in the number of stator slots Z = 6 to Z = 18 causes an approximately twofold decrease in the ripple factor, but torque increases by 5 %. Electromagnetic torque will be increased approximately by 24 %, if non-magnetic flux barriers are created in the rotor of the studied synchronous reluctance motor.

  12. Conical Bearingless Motor/Generators

    NASA Technical Reports Server (NTRS)

    Kascak, P.; Jansen, R.; Dever, T.

    2008-01-01

    Motor/generators based on conical magnetic bearings have been invented as an improved alternative to prior such machines based, variously, on radial and/or axial magnetic bearings. Both the present and prior machines are members of the class of so-called bearingless or self bearing (in the sense of not containing mechanical bearings) rotary machines. Each motor/generator provides both a torque and force allowing it to either function as a motor and magnetic bearing or a generator and magnetic bearing concurrently. Because they are not subject to mechanical bearing wear, these machines have potentially long operational lives and can function without lubrication and over wide ranges of speed and temperature that include conditions under which lubricants would become depleted, degraded, or ineffective and mechanical bearings would fail. The figure shows three typical configurations of conical bearingless motor/generators. The main elements of each motor/generator are concentric rotor and stator portions having conically tapered surfaces facing each other across a gap. Because a conical motor/generator imposes both radial and axial magnetic forces, it acts, in effect, as a combination of an axial and a radial magnetic bearing. Therefore, only two conical motor/generators - one at each end of a rotor - are needed to effect complete magnetic leviation of the rotor, whereas previously, it was necessary to use a combination of an axial and a radial magnetic bearing at each end of the rotor to achieve complete magnetic levitation and a separate motor to provide torque.

  13. Characteristic and magnetic field analysis of a high temperature superconductor axial-flux coreless induction maglev motor

    NASA Astrophysics Data System (ADS)

    Wei, Qin; Yu, Fan; Jin, Fang; Shuo, Li; Guoguo, Li; Gang, Lv

    2012-04-01

    A new high temperature superconductor axial-flux coreless maglev motor (HTS AFIM) is proposed, of which the primary windings are made of HTS tapes and the secondary is a non-magnetic conductor. The main works of this paper are the magnetic-field computation and characteristics analysis of HTS AFIM. For the first one, the reduction of magnetic fields near outer and inner radius of the HTS AFIM is solved by introducing the sub-loop electro-magnetic model along the radial position. For the second one, the AC losses of HTS coils are calculated. The relationships between the device's characteristics and device parameters are presented, and the results indicate that under certain frequency and current levitation device can output enough lift force. The conclusions are verified by finite element calculations.

  14. Numerical analysis of the symmetric hybrid transducer ultrasonic motor.

    PubMed

    Satonobu, J; Friend, J R; Nakamura, K; Ueha, S

    2001-11-01

    In this paper, operation of a symmetric hybrid transducer ultrasonic motor with output produced by two rotors connected together via a driveshaft is numerically analyzed and compared with the traditional asymmetric hybrid transducer motor design that produces its output from only one rotor. A one-dimensional finite element model for torsional vibration in the stator and a Coulomb friction model for rotor/stator contact associated with the longitudinal vibration of the motor are introduced. The calculation results demonstrate that the symmetric design is capable of performance comparable with the traditional asymmetric design when an optimum static spring force in the rotor/stator contact interface is applied during operation.

  15. State observer for synchronous motors

    DOEpatents

    Lang, Jeffrey H.

    1994-03-22

    A state observer driven by measurements of phase voltages and currents for estimating the angular orientation of a rotor of a synchronous motor such as a variable reluctance motor (VRM). Phase voltages and currents are detected and serve as inputs to a state observer. The state observer includes a mathematical model of the electromechanical operation of the synchronous motor. The characteristics of the state observer are selected so that the observer estimates converge to the actual rotor angular orientation and velocity, winding phase flux linkages or currents.

  16. Counterrotating brushless DC permanent magnet motor

    NASA Astrophysics Data System (ADS)

    Hawsey, R. A.; Bailey, J. M.

    1990-07-01

    A brushless DC permanent magnet motor is provided for driving an autonomous underwater vehicle. In one embodiment, the motor comprises four substantially flat stators disposed in stacked relationship, with pairs of the stators being axially spaced and each of the stators comprising a tape-wound stator coil; first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of embedded permanent magnets. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and the drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs, and rotors mounted on opposite sides of the stators and driven by counterrotating shafts.

  17. Reducing rotor weight

    SciTech Connect

    Cheney, M.C.

    1997-12-31

    The cost of energy for renewables has gained greater significance in recent years due to the drop in price in some competing energy sources, particularly natural gas. In pursuit of lower manufacturing costs for wind turbine systems, work was conducted to explore an innovative rotor designed to reduce weight and cost over conventional rotor systems. Trade-off studies were conducted to measure the influence of number of blades, stiffness, and manufacturing method on COE. The study showed that increasing number of blades at constant solidity significantly reduced rotor weight and that manufacturing the blades using pultrusion technology produced the lowest cost per pound. Under contracts with the National Renewable Energy Laboratory and the California Energy Commission, a 400 kW (33m diameter) turbine was designed employing this technology. The project included tests of an 80 kW (15.5m diameter) dynamically scaled rotor which demonstrated the viability of the design.

  18. Open Rotor Spin Test

    NASA Video Gallery

    An open rotor, also known as a high-speed propeller, is tested in a wind tunnel. The propeller moves much more quickly than a standard propeller, and the blades of the propeller are shaped differen...

  19. Hall effect encoding of brushless dc motors

    NASA Technical Reports Server (NTRS)

    Berard, C. A.; Furia, T. J.; Goldberg, E. A.; Greene, R. C.

    1970-01-01

    Encoding mechanism integral to the motor and using the permanent magnets embedded in the rotor eliminates the need for external devices to encode information relating the position and velocity of the rotating member.

  20. Torque-Summing Brushless Motor

    NASA Technical Reports Server (NTRS)

    Vaidya, J. G.

    1986-01-01

    Torque channels function cooperatively but electrically independent for reliability. Brushless, electronically-commutated dc motor sums electromagnetic torques on four channels and applies them to single shaft. Motor operates with any combination of channels and continues if one or more of channels fail electrically. Motor employs single stator and rotor and mechanically simple; however, each of channels electrically isolated from other so that failure of one does not adversely affect others.

  1. Type-2 fuzzy logic control based MRAS speed estimator for speed sensorless direct torque and flux control of an induction motor drive.

    PubMed

    Ramesh, Tejavathu; Kumar Panda, Anup; Shiva Kumar, S

    2015-07-01

    In this research study, a model reference adaptive system (MRAS) speed estimator for speed sensorless direct torque and flux control (DTFC) of an induction motor drive (IMD) using two adaptation mechanism schemes are proposed to replace the conventional proportional integral controller (PIC). The first adaptation mechanism scheme is based on Type-1 fuzzy logic controller (T1FLC), which is used to achieve high performance sensorless drive in both transient as well as steady state conditions. However, the Type-1 fuzzy sets are certain and unable to work effectively when higher degree of uncertainties presents in the system which can be caused by sudden change in speed or different load disturbances, process noise etc. Therefore, a new Type-2 fuzzy logic controller (T2FLC) based adaptation mechanism scheme is proposed to better handle the higher degree of uncertainties and improves the performance and also robust to various load torque and sudden change in speed conditions, respectively. The detailed performances of various adaptation mechanism schemes are carried out in a MATLAB/Simulink environment with a speed sensor and speed sensorless modes of operation when an IMD is operating under different operating conditions, such as, no-load, load and sudden change in speed, respectively. To validate the different control approaches, the system also implemented on real-time system and adequate results are reported for its validation.

  2. Parametric Blade Study Test Report Rotor Configuration. Number 1

    DTIC Science & Technology

    1988-11-01

    Lauderdale, Florida) provides a visual indication of rotor speed accurate to ten RPM. The tachometer also includes an adjustable speed limiting switch as...elevated power requirements for the drive motor at 90-100% of design speed caused the motor windings to overheat. To permit adequate test time at these...Puterbaugh Technology Branch Turbine Engine Division November 1988 Interim Report for Period 1 January 1987 - 31 May 1988 Distribution to U.S. government

  3. Torque Control of a Separate-Winding Excitation DC Motor for a Dynamometer

    DTIC Science & Technology

    2010-12-01

    DFIG system is shown in Figure 1 [4]. 2 Figure 1. Doubly-fed induction generator wind turbine system, from [4]. To simulate wind speed and...generator wind turbine system modified, from [4]. 3 Use of a DC motor [3] is a cheap and efficient way to provide torque and speed to the system for lab...and field windings , and rω is the rotor speed . An equivalent circuit of a DC machine, shown in Figure 4, defines where these variables are

  4. Electrostatic generator/motor configurations

    DOEpatents

    Post, Richard F

    2014-02-04

    Electrostatic generators/motors designs are provided that generally may include a first cylindrical stator centered about a longitudinal axis; a second cylindrical stator centered about the axis, a first cylindrical rotor centered about the axis and located between the first cylindrical stator and the second cylindrical stator. The first cylindrical stator, the second cylindrical stator and the first cylindrical rotor may be concentrically aligned. A magnetic field having field lines about parallel with the longitudinal axis is provided.

  5. Aerodynamic design of the National Rotor Testbed.

    SciTech Connect

    Kelley, Christopher Lee

    2015-10-01

    A new wind turbine blade has been designed for the National Rotor Testbed (NRT) project and for future experiments at the Scaled Wind Farm Technology (SWiFT) facility with a specific focus on scaled wakes. This report shows the aerodynamic design of new blades that can produce a wake that has similitude to utility scale blades despite the difference in size and location in the atmospheric boundary layer. Dimensionless quantities circulation, induction, thrust coefficient, and tip-speed-ratio were kept equal between rotor scales in region 2 of operation. The new NRT design matched the aerodynamic quantities of the most common wind turbine in the United States, the GE 1.5sle turbine with 37c model blades. The NRT blade design is presented along with its performance subject to the winds at SWiFT. The design requirements determined by the SWiFT experimental test campaign are shown to be met.

  6. Direct-drive field actuator motors

    DOEpatents

    Grahn, A.R.

    1995-07-11

    A high-torque, low speed, positive-drive field actuator motor is disclosed including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately. 37 figs.

  7. Direct-drive field actuator motors

    SciTech Connect

    Grahn, Allen R.

    1995-01-01

    A high-torque, low speed, positive-drive field actuator motor including a stator carrying at least one field actuator which changes in dimension responsive to application of an energy field, and at least one drive shoe movable by the dimensional changes of the field actuator to contact and move a rotor element with respect to the stator. Various embodiments of the motor are disclosed, and the rotor element may be moved linearly or arcuately.

  8. Enclosure Requirements to Protect Personnel from Spinning Rotor Frailures at the Power Electronics and Electric Machinery Research Center

    SciTech Connect

    McKeever, John W

    2007-08-01

    Performance evaluation of electric motors is a major function of the Power Electronics and Electric Machinery Research Center (PEEMRC). Normally these motors have a fixed wire-wound stator and a rotating rotor, which may have conductors embedded in a ferromagnetic core (induction motors), magnets mounted on the surface of the ferromagnetic core with a thin metal or composite cylinder or ring to hold them in place, or magnets embedded in the ferromagnetic core. Most of the work currently involves the last two permanent magnet (PM) configurations. Although the stator of a radial-gap motor can absorb energy from many of the fragments ejected from the rotor during operation, the stator of an axial-gap motor is not positioned to provide significant protection. The housing of each motor can also absorb some of the energy. The most conservative approach, however, is to assume that all fragments from the rotor must be contained by a protective enclosure. An ideal enclosure is transparent. Manufacturers of such plastics as Lexan, Tuffak, and Cyrolon sell different variations of transparent enclosure material. Lexan is a polycarbonate sheet. Lexgard{reg_sign} is a penetration resistant material made by layering polycarbonate material between pieces of ordinary glass. A fragment striking a sheet of enclosure material will pierce the surface layer, but the layered polycarbonate-glass material is able to absorb the fragment's energy before it completes penetration. Tuffak{reg_sign} is Lexan polycarbonate. Cyrolon{reg_sign} bullet resistant material is acrylic sheet. The ability of the enclosure to stop a fragment depends on its thickness as well as the penetration capability of the fragment; for example, a lead fragment has much less penetrating capability than a steel fragment. Enclosure thicknesses are commercially available to provide several levels of protection. These levels depend on the momentum of the fragments and have been evaluated for some common types of ammunition

  9. Steady-state analysis of a faulted three-phase four-wire system supplying induction motors with neutrals connected and other single-phase line-to-neutral loads

    NASA Technical Reports Server (NTRS)

    Wood, M. E.

    1980-01-01

    Four wire Wye connected ac power systems exhibit peculiar steady state fault characteristics when the fourth wire of three phase induction motors is connected. The loss of one phase of power source due to a series or shunt fault results in currents higher than anticipated on the remaining two phases. A theoretical approach to compute the fault currents and voltages is developed. A FORTRAN program is included in the appendix.

  10. Tilt rotor aircraft aeroacoustics

    NASA Technical Reports Server (NTRS)

    George, Albert R.; Smith, Charles A.; Maisel, Martin D.; Brieger, John T.

    1989-01-01

    This paper studies the state of knowledge and the needed improvement in noise methodology and measurements for tilt rotor aircraft. Similarities and differences between tilt rotor aeroacoustic conditions and helicopter and propeller experience are identified. A discussion of the possible principal noise mechanisms throughout the flight envelope shows a need for further experimental and analytical investigations to develop an adequate understanding of the important sources and influencing factors. Existing experimental data from flight tests suggest terminal area noise reduction by operating within certain portions of the conversion flight envelope. Prediction methods are found to provide approximate indications only for low frequency harmonic and broadband noise for several of the tilt rotor's operating conditions. The acoustic effects of the hover case 'fountain' flow are pronounced and need further research. Impulsive noise and high frequency harmonic noise remain problems, as on helicopters, pending major improvements in wake, unsteady aerodynamics, and acoustics methodology.

  11. Electric motor model repair specifications

    SciTech Connect

    1995-08-01

    These model repair specifications list the minimum requirements for repair and overhaul of polyphase AC squireel cage induction motors. All power ranges, voltages, and speeds of squirrel cage motors are covered.

  12. Rotor balancing apparatus and system

    NASA Technical Reports Server (NTRS)

    Lyman, Frank (Inventor); Lyman, Joseph (Inventor)

    1976-01-01

    Rotor balancing apparatus and a system comprising balance probes for measuring unbalance at the ends of a magnetically suspended rotor are disclosed. Each balance probe comprises a photocell which is located in relationship to the magnetically suspended rotor such that unbalance of the rotor changes the amount of light recorded by each photocell. The signal from each photocell is electrically amplified and displayed by a suitable device, such as an oscilloscope.

  13. Helicopter tail rotor noise analyses

    NASA Technical Reports Server (NTRS)

    George, A. R.; Chou, S. T.

    1986-01-01

    A study was made of helicopter tail rotor noise, particularly that due to interactions with the main rotor tip vortices, and with the fuselage separation mean wake. The tail rotor blade-main rotor tip vortex interaction is modelled as an airfoil of infinite span cutting through a moving vortex. The vortex and the geometry information required by the analyses are obtained through a free wake geometry analysis of the main rotor. The acoustic pressure-time histories for the tail rotor blade-vortex interactions are then calculated. These acoustic results are compared to tail rotor loading and thickness noise, and are found to be significant to the overall tail rotor noise generation. Under most helicopter operating conditions, large acoustic pressure fluctuations can be generated due to a series of skewed main rotor tip vortices passing through the tail rotor disk. The noise generation depends strongly upon the helicopter operating conditions and the location of the tail rotor relative to the main rotor.

  14. Wave rotor demonstrator engine assessment

    NASA Technical Reports Server (NTRS)

    Snyder, Philip H.

    1996-01-01

    The objective of the program was to determine a wave rotor demonstrator engine concept using the Allison 250 series engine. The results of the NASA LERC wave rotor effort were used as a basis for the wave rotor design. A wave rotor topped gas turbine engine was identified which incorporates five basic requirements of a successful demonstrator engine. Predicted performance maps of the wave rotor cycle were used along with maps of existing gas turbine hardware in a design point study. The effects of wave rotor topping on the engine cycle and the subsequent need to rematch compressor and turbine sections in the topped engine were addressed. Comparison of performance of the resulting engine is made on the basis of wave rotor topped engine versus an appropriate baseline engine using common shaft compressor hardware. The topped engine design clearly demonstrates an impressive improvement in shaft horsepower (+11.4%) and SFC (-22%). Off design part power engine performance for the wave rotor topped engine was similarly improved including that at engine idle conditions. Operation of the engine at off design was closely examined with wave rotor operation at less than design burner outlet temperatures and rotor speeds. Challenges identified in the development of a demonstrator engine are discussed. A preliminary design was made of the demonstrator engine including wave rotor to engine transition ducts. Program cost and schedule for a wave rotor demonstrator engine fabrication and test program were developed.

  15. Accurate identification of the frequency response functions for the rotor-bearing-foundation system using the modified pseudo mode shape method

    NASA Astrophysics Data System (ADS)

    Chen, Yeong-Shu; Cheng, Ye-Dar; Yang, Tachung; Koai, Kwang-Lu

    2010-03-01

    In this paper, an identification technique in the dynamic analyses of rotor-bearing-foundation systems called the pseudo mode shape method (PMSM) was improved in order to enhance the accuracy of the identified dynamic characteristic matrices of its foundation models. Two procedures, namely, phase modification and numerical optimisation, were proposed in the algorithm of PMSM to effectively improve its accuracy. Generally, it is always necessary to build the whole foundation model in studying the dynamics of a rotor system through the finite element analysis method. This is either unfeasible or impractical when the foundation is too complicated. Instead, the PMSM uses the frequency response function (FRF) data of joint positions between the rotor and the foundation to establish the equivalent mass, damping, and stiffness matrices of the foundation without having to build the physical model. However, the accuracy of the obtained system's FRF is still unsatisfactory, especially at those higher modes. In order to demonstrate the effectiveness of the presented methods, a solid foundation was solved for its FRF by using both the original and modified PMSM, as well as the finite element (ANSYS) model for comparisons. The results showed that the accuracy of the obtained FRF was improved remarkably with the modified PMSM based on the results of the ANSYS. In addition, an induction motor resembling a rotor-bearing-foundation system, with its housing treated as the foundation, was taken as an example to verify the algorithm experimentally. The FRF curves at the bearing supports of the rotor (armature) were obtained through modal testing to estimate the above-mentioned equivalent matrices of the housing. The FRF of the housing, which was calculated from the equivalent matrices with the modified PMSM, showed satisfactory consistency with that from the modal testing.

  16. A sensorless initial rotor position's estimation for permanent magnet synchronous machines

    NASA Astrophysics Data System (ADS)

    Krasnov, I.; Langraf, S.; Odnolopylov, I.; Koltun, V.

    2015-10-01

    Permanent magnet synchronous motors for the effective start require information about the initial position of a rotor. In this regard, most systems use position sensors, which substantially increase entirely a cost of an electrical drive [1-3]. The aim of this article is to develop a new method, allowing determining the absolute angular position of the permanent magnet synchronous motors’ rotor [4,5]. With a certain voltage pulses applied to the motor, its stator is magnetized by currents leakage in the windings. This allows using a special algorithm to calculate the absolute position of the rotor without using any motor parameters [6]. Simulation results prove the simplicity and efficiency of this method for determining an initial position of the permanent magnet synchronous motors’ rotor. Thus, this method can be widely used in the electrical industry.

  17. 77 FR 26607 - Energy Conservation Program: Test Procedures for Electric Motors and Small Electric Motors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-04

    ... methods, marking requirements, and energy efficiency levels for three-phase induction motors, March 2010... Performance of Single-Speed Three-Phase Cage Induction Motors, clauses 5.2, 5.4, 6, and 8, and Tables 1, 2, 3... Procedure for Polyphase Induction Motors and Generators, approved February 9, 2004: (i) Section...

  18. Permanent Magnet Generator Rotor Containment Study

    DTIC Science & Technology

    1983-05-01

    IN ORDER TO REDUCE THE ROTOR POLE FACE LOSSES, THE MAGNETIC SEGM=.E OF THE SHRINK RING IS CONSTRUCTED FROM THIN LAMINATIONS. AN AMORTISSEUR CIRCUIT...2.3.2 Non-Magnetic Shrink Ring 23 2.3.3 Pole Retained Magnets 25 2.3.4 Bi-Metallic Ring with 27 Surface Amortisseur 2.4 Selected Design 29 III...laminations. The amortisseur circuit comprising of three bars per pole is incorporated to reduce the commutating inductance of the generator and, thus, improve

  19. The Morrison Bearingless Switched Reluctance Motor

    NASA Technical Reports Server (NTRS)

    Wong, David S.

    2004-01-01

    Switched reluctance motors typically consist of pairs of poles protruding outward from a central rotor, surrounded by pairs of coils protruding inward from a stator. The pairs of coils, positioned a short distance from opposing sides of the rotor, are connected in series. A current runs through the coils, generating a magnetic flux between the coils. This attracts the protruding poles on the rotor, and just as the poles on the rotor approach the coils, the current to the coils is inverted, repelling the rotor s poles as they pass the coils. This current switching, back and forth, provides a continuous rotational torque to the rotor. reliability, durability, low cost, and operation in adverse environments such as high temperatures, extreme temperature variations, and high rotational speeds. However, because rotors are often manufactured with minute flaws due to imperfections in the machining process, traditional switched reluctance motors often suffer from substantial amounts of vibration. In addition, the current in the coils imparts a strong radial magnetic force on the rotor; the continuous alternating of the direction of this force also causes vibration. As a result, switched reluctance motors require bearings that, run at high speeds, can require lubrication apparatus and are subject to problems with heat and wear. My mentor s recent invention, the "Bearingless" Switched Reluctance Motor, actually uses magnetic bearings instead of traditional physical bearings. Sensors are used to continuously determine the position of the rotor. A computer reads the position sensor input, performs calculations, and outputs a current to a set of extra coils (in addition to the coils rotating the rotor). This current provides a magnetic force that counters and damps the vibration. The sense-calculate-update loop iterates more than thirty thousand times per second. For now, our goal is to have the rotor rotate at about 6000 rprn, and at that speed, the magnetic bearing is

  20. Implementation of a Non-Metallic Barrier in an Electric Motor

    NASA Technical Reports Server (NTRS)

    M'Sadoques, George A. (Inventor); Carra, Michael R. (Inventor); Beringer, Durwood M. (Inventor)

    2013-01-01

    A motor for use in a volatile environment includes a rotor exposed to the volatile environment, electronics for rotating the rotor, an impervious ceramic barrier separating the electronics and the rotor, and a flexible seal for preventing the volatile environment from contacting the electronics and for minimizing vibratory and twisting loads upon the barrier to minimize damage to the barrier.

  1. Rotor-stator contact dynamics using a non-ideal drive—Theoretical and experimental aspects

    NASA Astrophysics Data System (ADS)

    Lahriri, Said; Weber, Hans I.; Santos, Ilmar F.; Hartmann, Henning

    2012-09-01

    The possible contact between rotor and stator is considered a serious malfunction that may lead to catastrophic failure. Rotor rub is seen as a secondary phenomenon caused by a primary source, i.e. sudden mass unbalance, instabilities generated by aerodynamic and hydrodynamic forces in seals and bearings among others. The contact event gives rise to normal and friction forces exerted on the rotor at impact events. The friction force plays a significant role by transferring some rotational energy of the rotor to lateral motion. A mathematical model has been developed to capture this for a conventional backup annular guide setup. It is reasonable to superpose an impact condition to the rub, where the rotor spin energy can be fully transformed into rotor lateral movements. Using a nonideal drive, i.e. an electric motor without any kind of velocity feedback control, it is even possible to stop the rotor spin under rubbing conditions. All the rotational energy will be transformed in a kind of "self-excited" rotor lateral vibration with repeated impacts against the housing. This paper studies the impact motion of a rotor impacting a conventional backup annular guide for the case of dry and lubricated inner surface of the guide. For the dry surface case, the experimental and numerical analysis shows that the rotational energy is fully transformed into lateral motion and the rotor spin is stopped. Based on this study this paper proposes a new unconventional backup bearing design in order to reduce the rub related severity in friction and center the rotor at impact events. The analysis shows that the rotor at impacts is forced to the center of the backup bearing and the lateral motion is mitigated. As a result of this, the rotor spin is kept constant.

  2. Acoustic test of a model rotor and tail rotor: Results for the isolated rotors and combined configuration

    NASA Technical Reports Server (NTRS)

    Martin, R. M.; Burley, C. L.; Elliott, J. W.

    1989-01-01

    Acoustic data from a model scale main rotor and tail rotor experiment in the NASA Langley 14 by 22 Foot Subsonic Tunnel are presented for the main rotor and trail rotor in isolation and for the two rotors operating together. Results for the isolated main rotor show the importance of the rotor flapping conditions on mid-frequency noise content. High levels of main rotor retreating side blade-vortex interaction noise are shown to radiate downstream of the model. The isolated tail rotor noise results show the dominance of harmonic noise in the thrusting direction. The occurrence of tail rotor broadband noise is seen by the broadening of the tail rotor harmonics and is attributed to fuselage wake turbulence. The combined main and tail rotor data are presented to show the dominance of each rotor's different noise sources at different directivity locations.

  3. Drive system for the retraction/extension of variable diameter rotor systems

    NASA Technical Reports Server (NTRS)

    Gmirya, Yuriy (Inventor)

    2003-01-01

    A drive system for a variable diameter rotor (VDR) system includes a plurality of rotor blade assemblies with inner and outer rotor blade segments. The outer blade segment being telescopically mounted to the inner blade segment. The VDR retraction/extension system includes a drive housing mounted at the root of each blade. The housing supports a spool assembly, a harmonic gear set and an electric motor. The spool assembly includes a pair of counter rotating spools each of which drive a respective cable which extends through the interior of the inboard rotor blade section and around a pulley mounted to the outboard rotor blade section. In operation, the electric motor drives the harmonic gear set which rotates the counter rotating spools. Rotation of the spools causes the cables to be wound onto or off their respective spool consequently effecting retraction/extension of the pulley and the attached outboard rotor blade section relative the inboard rotor blade section. As each blade drive system is independently driven by a separate electrical motor, each independent VDR blade assembly is independently positionable.

  4. Submersible canned motor mixer pump

    DOEpatents

    Guardiani, R.F.; Pollick, R.D.

    1997-10-07

    A mixer pump is described used in a waste tank for mobilizing high-level radioactive liquid waste having a column assembly containing power cables, a motor housing with electric motor means which includes a stator can of a stator assembly and a rotor can of a rotor assembly, and an impeller assembly with an impeller connected to a shaft of the rotor assembly. The column assembly locates the motor housing with the electric motor means adjacent to the impeller which creates an hydraulic head, and which forces the liquid waste into the motor housing to cool the electric motor means and to lubricate radial and thrust bearing assemblies. Hard-on-hard bearing surfaces of the bearing assemblies and a ring assembly between the impeller and electric motor means act to grind down large particles in the liquid waste flow. These larger particles are received in slots in the static bearing members of the radial bearing assemblies. Only solid waste particles smaller than the clearances in the system can pass there through, thereby resisting damage to and the interruption of the operation of the mixer pump. 10 figs.

  5. Submersible canned motor mixer pump

    DOEpatents

    Guardiani, Richard F.; Pollick, Richard D.

    1997-01-01

    A mixer pump used in a waste tank for mobilizing high-level radioactive liquid waste having a column assembly containing power cables, a motor housing with electric motor means which includes a stator can of a stator assembly and a rotor can of a rotor assembly, and an impeller assembly with an impeller connected to a shaft of the rotor assembly. The column assembly locates the motor housing with the electric motor means adjacent to the impeller which creates an hydraulic head, and which forces the liquid waste into the motor housing to cool the electric motor means and to lubricate radial and thrust bearing assemblies. Hard-on-hard bearing surfaces of the bearing assemblies and a ring assembly between the impeller and electric motor means act to grind down large particles in the liquid waste flow. These larger particles are received in slots in the static bearing members of the radial bearing assemblies. Only solid waste particles smaller than the clearances in the system can pass therethrough, thereby resisting damage to and the interruption of the operation of the mixer pump.

  6. Effect of phase advance on the brushless dc motor torque speed respond

    NASA Astrophysics Data System (ADS)

    Mohd, M. S.; Karsiti, M. N.; Mohd, M. S.

    2015-12-01

    Brushless direct current (BLDC) motor is widely used in small and medium sized electric vehicles as it exhibit highest specific power and thermal efficiency as compared to the induction motor. Permanent magnets BLDC rotor create a constant magnetic flux, which limit the motor top speed. As the back electromotive force (EMF) voltage increases proportionally with motor rotational speed and it approaches the amplitude of the input voltage, the phase current amplitude will reach zero. By advancing the phase current, it is possible to extend the maximum speed of the BLDC motor beyond the rated top speed. This will allow smaller BLDC motor to be used in small electric vehicles (EV) and in larger applications will allow the use of BLDC motor without the use of multispeed transmission unit for high speed operation. However, increasing the speed of BLDC will affect the torque speed response. The torque output will decrease as speed increases. Adjusting the phase angle will affect the speed of the motor as each coil is energized earlier than the corresponding rise in the back emf of the coil. This paper discusses the phase advance strategy of Brushless DC motor by phase angle manipulation approaches using external hall sensors. Tests have been performed at different phase advance angles in advance and retard positions for different voltage levels applied. The objective is to create the external hall sensor system to commutate the BLDC motor, to establish the phase advance of the BLDC by varying the phase angle through external hall sensor manipulation, observe the respond of the motor while applying the phase advance by hall sensor adjustment.

  7. Variable camber rotor study

    NASA Technical Reports Server (NTRS)

    Dadone, L.; Cowan, J.; Mchugh, F. J.

    1982-01-01

    Deployment of variable camber concepts on helicopter rotors was analytically assessed. It was determined that variable camber extended the operating range of helicopters provided that the correct compromise can be obtained between performance/loads gains and mechanical complexity. A number of variable camber concepts were reviewed on a two dimensional basis to determine the usefulness of leading edge, trailing edge and overall camber variation schemes. The most powerful method to vary camber was through the trailing edge flaps undergoing relatively small motions (-5 deg to +15 deg). The aerodynamic characteristics of the NASA/Ames A-1 airfoil with 35% and 50% plain trailing edge flaps were determined by means of current subcritical and transonic airfoil design methods and used by rotor performance and loads analysis codes. The most promising variable camber schedule reviewed was a configuration with a 35% plain flap deployment in an on/off mode near the tip of a blade. Preliminary results show approximately 11% reduction in power is possible at 192 knots and a rotor thrust coefficient of 0.09. The potential demonstrated indicates a significant potential for expanding the operating envelope of the helicopter. Further investigation into improving the power saving and defining the improvement in the operational envelope of the helicopter is recommended.

  8. Single rotor turbine engine

    DOEpatents

    Platts, David A.

    2002-01-01

    There has been invented a turbine engine with a single rotor which cools the engine, functions as a radial compressor, pushes air through the engine to the ignition point, and acts as an axial turbine for powering the compressor. The invention engine is designed to use a simple scheme of conventional passage shapes to provide both a radial and axial flow pattern through the single rotor, thereby allowing the radial intake air flow to cool the turbine blades and turbine exhaust gases in an axial flow to be used for energy transfer. In an alternative embodiment, an electric generator is incorporated in the engine to specifically adapt the invention for power generation. Magnets are embedded in the exhaust face of the single rotor proximate to a ring of stationary magnetic cores with windings to provide for the generation of electricity. In this alternative embodiment, the turbine is a radial inflow turbine rather than an axial turbine as used in the first embodiment. Radial inflow passages of conventional design are interleaved with radial compressor passages to allow the intake air to cool the turbine blades.

  9. Stepper motor control that adjusts to motor loading

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor); Nola, Frank J. (Inventor)

    2000-01-01

    A system and method are provided for controlling a stepper motor having a rotor and a multi-phase stator. Sinusoidal command signals define a commanded position of the motor's rotor. An actual position of the rotor is sensed as a function of an electrical angle between the actual position and the commanded position. The actual position is defined by sinusoidal position signals. An adjustment signal is generated using the sinusoidal command signals and sinusoidal position signals. The adjustment signal is defined as a function of the cosine of the electrical angle. The adjustment signal is multiplied by each sinusoidal command signal to generate a corresponding set of excitation signals, each of which is applied to a corresponding phase of the multi-phase stator.

  10. Investigation of Combined Motor/Magnetic Bearings for Flywheel Energy Storage Systems

    NASA Technical Reports Server (NTRS)

    Hofmann, Heath

    2003-01-01

    Dr. Hofmann's work in the summer of 2003 consisted of two separate projects. In the first part of the summer, Dr. Hofmann prepared and collected information regarding rotor losses in synchronous machines; in particular, machines with low rotor losses operating in vacuum and supported by magnetic bearings, such as the motor/generator for flywheel energy storage systems. This work culminated in a presentation at NASA Glenn Research Center on this topic. In the second part, Dr. Hofmann investigated an approach to flywheel energy storage where the phases of the flywheel motor/generator are connected in parallel with the phases of an induction machine driving a mechanical actuator. With this approach, additional power electronics for driving the flywheel unit are not required. Simulations of the connection of a flywheel energy storage system to a model of an electromechanical actuator testbed at NASA Glenn were performed that validated the proposed approach. A proof-of-concept experiment using the D1 flywheel unit at NASA Glenn and a Sundstrand induction machine connected to a dynamometer was successfully conducted.

  11. Method and apparatus for assembling permanent magnet rotors

    DOEpatents

    Hsu, J.S.; Adams, D.J.

    1999-06-22

    A permanent magnet assembly for assembly in large permanent magnet motors and generators includes a two-piece carrier that can be slid into a slot in the rotor and then secured in place using a set screw. The invention also provides an auxiliary carrier device with guide rails that line up with the teeth of the rotor, so that a permanent magnet assembly can be pushed first into a slot, and then down the slot to its proper location. An auxiliary tool is provided to move the permanent magnet assembly into position in the slot before it is secured in place. Methods of assembling and disassembling the magnet assemblies in the rotor are also disclosed. 2 figs.

  12. Method and apparatus for assembling permanent magnet rotors

    DOEpatents

    Hsu, John S.; Adams, Donald J.

    1999-01-01

    A permanent magnet assembly (22) for assembly in large permanent magnet (PM) motors and generators includes a two-piece carrier (23, 24) that can be slid into a slot (13) in the rotor (10) and then secured in place using a set screw (37). The invention also provides an auxiliary carrier device (50) with guide rails (51) that line up with the teeth (12) of the rotor, so that a permanent magnet assembly (22) can be pushed first into a slot (13), and then down the slot (13) to its proper location. An auxiliary tool (50) is provided to move the permanent magnet assembly (22) into position in the slot (13) before it is secured in place. Methods of assembling and disassembling the magnet assemblies (22) in the rotor (10) are also disclosed.

  13. Development of a Switched Reluctance Motor made of Permendur

    NASA Astrophysics Data System (ADS)

    Hasegawa, Y.; Nakamura, K.; Ichinokura, O.

    2011-01-01

    A switched reluctance (SR) motor consists of stator and rotor cores, and windings. Both the stator and rotor have salient poles. The stator has concentrated windings on each salient pole. On the other hand, the rotor has no windings and no permanent magnets. Therefore, the SR motor is a low cost, extremely robust, and wide-range variable-speed motor. The performance of the SR motor greatly depends on magnetic properties of core material since it consists of only iron cores and windings. This paper presents the development of a novel SR motor made of permendur which has extremely high saturation flux density and very low core loss. Two types of SR motors, one is made of conventional non-oriented Si steel, the other is made of permendur, are compared by simulation and experiment. It is demonstrated that the torque of the SR motor made of permendur is greater than that of the conventional Si steel by 20%.

  14. Halbach array generator/motor having an automatically regulated output voltage and mechanical power output

    DOEpatents

    Post, Richard F.

    2005-02-22

    A motor/generator having its stationary portion, i.e., the stator, positioned concentrically within its rotatable element, i.e., the rotor, along its axis of rotation. The rotor includes a Halbach array. The stator windings are switched or commutated to provide a DC motor/generator much the same as in a conventional DC motor/generator. The voltage and power are automatically regulated by using centrifugal force to change the diameter of the rotor, and thereby vary the radial gap in between the stator and the rotating Halbach array, as a function of the angular velocity of the rotor.

  15. Ultrasonic Motors (USM) - an emerging actuation technology for planetary applications

    NASA Technical Reports Server (NTRS)

    Bao, X.; Das, H.

    2000-01-01

    A hybrid model that addressed a complete ultrasonic motor as a system was developed. The model allows using powerful commercial FE package to express dynamic characteristics of the stator and the rotor in engineering practice. An analog model couples the finite element models for the stator and rotor for the stator-interface layer-rotor syste. The model provides reasonably accurate results for CAD.

  16. Sensorless, online motor diagnostics

    SciTech Connect

    Kliman, G.B.; Premerlani, W.J.; Yazici, B.; Koegl, R.A.; Mazereeuw, J.

    1997-04-01

    Electric motors play a very important role in the safe and efficient running of any industrial plant. Early detection of abnormalities in the motors will help avoid expensive failures. Motor current signature analysis (MCSA) implemented in a computer-based motor monitor can contribute to such condition-based maintenance functions. Such a system may also detect an abnormality in the process as well as the motor. Extensive online monitoring of the motors can lead to greater plant availability, extended plant life, higher quality product, and smoother plant operation. With advances in digital technology over the last several years, adequate data processing capability is now available on cost-effective, microprocessor-based, protective-relay platforms to monitor motors for a variety of abnormalities in addition to the normal protection functions. Such multifunction monitors, first introduced by Multilin, are displacing the multiplicity of electromechanical devices commonly applied for many years. Following some background information on motor monitoring, this article features recent developments in providing tools for the diagnosis of faults or incipient faults in electric motor drives: Sensorless torque measurement, direct detection of turn-to-turn short circuits, detection of cracked or broken rotor bars, and detection of bearing deterioration.

  17. 14 CFR 29.921 - Rotor brake.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.921 Rotor brake. If there is a means to control the rotation of the rotor drive system independently of the engine, any limitations...

  18. Development of flexible rotor balancing criteria

    NASA Technical Reports Server (NTRS)

    Walter, W. W.; Rieger, N. F.

    1979-01-01

    Several studies in which analytical procedures were used to obtain balancing criteria for flexible rotors are described. General response data for a uniform rotor in damped flexible supports were first obtained for plain cylindrical bearings, tilting pad bearings, axial groove bearings, and partial arc bearings. These data formed the basis for the flexible rotor balance criteria presented. A procedure by which a practical rotor in bearings could be reduced to an equivalent uniform rotor was developed and tested. It was found that the equivalent rotor response always exceeded to practical rotor response by more than sixty percent for the cases tested. The equivalent rotor procedure was then tested against six practical rotor configurations for which data was available. It was found that the equivalent rotor method offered a procedure by which balance criteria could be selected for practical flexible rotors, using the charts given for the uniform rotor.

  19. 14 CFR 27.921 - Rotor brake.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.921 Rotor brake. If there is a means to control the rotation of the rotor drive system independently of the engine, any limitations...

  20. Ironless-armature brushless motor

    NASA Technical Reports Server (NTRS)

    Fisher, R. L.

    1977-01-01

    Device uses 12-pole samarium cobalt permanent-magnet rotor and three Hall-effect sensors for commutation. In prototype motor, torque constant (3-phase delta) is 65 oz-in/amp; electrical time constant (L/R) is 0.2 x 0.001 sec, and armature resistance is 20 ohms.

  1. Integrated technology rotor/flight research rotor concept definition study

    NASA Technical Reports Server (NTRS)

    Carlson, R. G.; Beno, E. A.; Ulisnik, H. D.

    1983-01-01

    As part of the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) Program a number of advanced rotor system designs were conceived and investigated. From these, several were chosen that best meet the started ITR goals with emphasis on stability, reduced weight and hub drag, simplicity, low head moment stiffness, and adequate strength and fatigue life. It was concluded that obtaining low hub moment stiffness was difficult when only the blade flexibility of bearingless rotor blades is considered, unacceptably low fatigue life being the primary problem. Achieving a moderate hub moment stiffness somewhat higher than state of the art articulated rotors in production today is possible within the fatigue life constraint. Alternatively, low stiffness is possible when additional rotor elements, besides the blades themselves, provide part of the rotor flexibility. Two primary designs evolved as best meeting the general ITR requirements that presently exist. An I shaped flexbeam with an external torque tube can satisfy the general goals but would have either higher stiffness or reduced fatigue life. The elastic gimbal rotor can achieve a better combination of low stiffness and high fatigue life but would be a somewhat heavier design and possibly exhibit a higher risk of aeromechanical instability.

  2. Direct analysis of transonic rotor noise with CFD technique

    NASA Astrophysics Data System (ADS)

    Aoyama, Takashi; Saito, Shigeru

    1994-06-01

    Three-dimensional Euler equations are directly solved to analyze the High-Speed Impulsive (HSI) noise of a helicopter motor by using CFD technique. The MSI noise is one of the most important sources of helicopter noise. It is generated on the advancing side of a helicopter caused by the shock wave on a blade surface. Although the method which solves the Ffowcs-Williams and Hawkings equation has been often used to analyze the subsonic rotor noise, it doesn't success to predict the transonic rotor noise such as the HSI noise With the advance of CFD technique, the calculation of the HSI noise is recently performed by the combined method of CFD with the Kirchhoff's equation or by the direct simulation using CFD technique. The latter has not been studied enough because huge number of grids are needed to capture the propagation of sound from a blade to an observer located in a far field. So, the powerful supercomputer of NAL, Numerical Wind Tunnel (NWT) is employed to calculate the RSI noise of a non-lifting hovering rotor directly by using the method. The numerical method to solve the governing equation is an implicit finite-difference scheme which utilizes a higher-order upwind scheme based on TVD. As a result, it is observed that the calculated wave form is in very good agreement with an experimental data at sonic cylinder. The agreement is not very good at about three rotor radii but is reasonable at about two rotor radii.

  3. Electric vehicle motors and controllers

    NASA Technical Reports Server (NTRS)

    Secunde, R. R.

    1981-01-01

    Improved and advanced components being developed include electronically commutated permanent magnet motors of both drum and disk configuration, an unconventional brush commutated motor, and ac induction motors and various controllers. Test results on developmental motors, controllers, and combinations thereof indicate that efficiencies of 90% and higher for individual components, and 80% to 90% for motor/controller combinations can be obtained at rated power. The simplicity of the developmental motors and the potential for ultimately low cost electronics indicate that one or more of these approaches to electric vehicle propulsion may eventually displace presently used controllers and brush commutated dc motors.

  4. Torque meter aids study of hysteresis motor rings

    NASA Technical Reports Server (NTRS)

    Cole, M.

    1967-01-01

    Torque meter, simulating hysteresis motor operation, allows rotor ring performance characteristics to be analyzed. The meter determines hysteresis motor torque and actual stresses of the ring due to its mechanical situation and rotation, aids in the study of asymmetries or defects in motor rings, and measures rotational hysteresis.

  5. Application of Synchronous Brushless Motors in Electric Hand Tools

    NASA Astrophysics Data System (ADS)

    Dirba, J.; Lavrinovicha, L.; Levin, N.; Pugachev, V.

    2012-01-01

    In the paper, the possibilities to apply synchronous brushless motors in the electric hand tools are considered. The potential of such motors is estimated in a wide range of characteristics. In particular, estimation is made for the electric hand plane with a synchronous motor having outer rotor and excitation from permanent magnets.

  6. Internal rotor friction instability

    NASA Technical Reports Server (NTRS)

    Walton, J.; Artiles, A.; Lund, J.; Dill, J.; Zorzi, E.

    1990-01-01

    The analytical developments and experimental investigations performed in assessing the effect of internal friction on rotor systems dynamic performance are documented. Analytical component models for axial splines, Curvic splines, and interference fit joints commonly found in modern high speed turbomachinery were developed. Rotor systems operating above a bending critical speed were shown to exhibit unstable subsynchronous vibrations at the first natural frequency. The effect of speed, bearing stiffness, joint stiffness, external damping, torque, and coefficient of friction, was evaluated. Testing included material coefficient of friction evaluations, component joint quantity and form of damping determinations, and rotordynamic stability assessments. Under conditions similar to those in the SSME turbopumps, material interfaces experienced a coefficient of friction of approx. 0.2 for lubricated and 0.8 for unlubricated conditions. The damping observed in the component joints displayed nearly linear behavior with increasing amplitude. Thus, the measured damping, as a function of amplitude, is not represented by either linear or Coulomb friction damper models. Rotordynamic testing of an axial spline joint under 5000 in.-lb of static torque, demonstrated the presence of an extremely severe instability when the rotor was operated above its first flexible natural frequency. The presence of this instability was predicted by nonlinear rotordynamic time-transient analysis using the nonlinear component model developed under this program. Corresponding rotordynamic testing of a shaft with an interference fit joint demonstrated the presence of subsynchronous vibrations at the first natural frequency. While subsynchronous vibrations were observed, they were bounded and significantly lower in amplitude than the synchronous vibrations.

  7. Fluid powered linear piston motor with harmonic coupling

    DOEpatents

    Raymond, David W.

    2016-09-20

    A motor is disclosed that includes a module assembly including a piston that is axially cycled. The piston axial motion is coupled to torque couplers that convert the axial motion into rotary motion. The torque couplers are coupled to a rotor to rotate the rotor.

  8. Molecular Rotors as Switches

    PubMed Central

    Xue, Mei; Wang, Kang L.

    2012-01-01

    The use of a functional molecular unit acting as a state variable provides an attractive alternative for the next generations of nanoscale electronics. It may help overcome the limits of conventional MOSFETd due to their potential scalability, low-cost, low variability, and highly integratable characteristics as well as the capability to exploit bottom-up self-assembly processes. This bottom-up construction and the operation of nanoscale machines/devices, in which the molecular motion can be controlled to perform functions, have been studied for their functionalities. Being triggered by external stimuli such as light, electricity or chemical reagents, these devices have shown various functions including those of diodes, rectifiers, memories, resonant tunnel junctions and single settable molecular switches that can be electronically configured for logic gates. Molecule-specific electronic switching has also been reported for several of these device structures, including nanopores containing oligo(phenylene ethynylene) monolayers, and planar junctions incorporating rotaxane and catenane monolayers for the construction and operation of complex molecular machines. A specific electrically driven surface mounted molecular rotor is described in detail in this review. The rotor is comprised of a monolayer of redox-active ligated copper compounds sandwiched between a gold electrode and a highly-doped P+ Si. This electrically driven sandwich-type monolayer molecular rotor device showed an on/off ratio of approximately 104, a read window of about 2.5 V, and a retention time of greater than 104 s. The rotation speed of this type of molecular rotor has been reported to be in the picosecond timescale, which provides a potential of high switching speed applications. Current-voltage spectroscopy (I-V) revealed a temperature-dependent negative differential resistance (NDR) associated with the device. The analysis of the device I–V characteristics suggests the source of the

  9. None of the rotor residues of F1-ATPase are essential for torque generation.

    PubMed

    Chiwata, Ryohei; Kohori, Ayako; Kawakami, Tomonari; Shiroguchi, Katsuyuki; Furuike, Shou; Adachi, Kengo; Sutoh, Kazuo; Yoshida, Masasuke; Kinosita, Kazuhiko

    2014-05-20

    F1-ATPase is a powerful rotary molecular motor that can rotate an object several hundred times as large as the motor itself against the viscous friction of water. Forced reverse rotation has been shown to lead to ATP synthesis, implying that the mechanical work against the motor's high torque can be converted into the chemical energy of ATP. The minimal composition of the motor protein is α3β3γ subunits, where the central rotor subunit γ turns inside a stator cylinder made of alternately arranged α3β3 subunits using the energy derived from ATP hydrolysis. The rotor consists of an axle, a coiled coil of the amino- and carboxyl-terminal α-helices of γ, which deeply penetrates the stator cylinder, and a globular protrusion that juts out from the stator. Previous work has shown that, for a thermophilic F1, significant portions of the axle can be truncated and the motor still rotates a submicron sized bead duplex, indicating generation of up to half the wild-type (WT) torque. Here, we inquire if any specific interactions between the stator and the rest of the rotor are needed for the generation of a sizable torque. We truncated the protruding portion of the rotor and replaced part of the remaining axle residues such that every residue of the rotor has been deleted or replaced in this or previous truncation mutants. This protrusionless construct showed an unloaded rotary speed about a quarter of the WT, and generated one-third to one-half of the WT torque. No residue-specific interactions are needed for this much performance. F1 is so designed that the basic rotor-stator interactions for torque generation and control of catalysis rely solely upon the shape and size of the rotor at very low resolution. Additional tailored interactions augment the torque to allow ATP synthesis under physiological conditions.

  10. Analysis of a teetered, variable-speed rotor: final report

    SciTech Connect

    Weber, T L; Wilson, R E; Walker, S N

    1991-06-01

    A computer model of a horizontal axis wind turbine (HOOT) with four structural degrees of freedom has been derived and verified. The four degrees of freedom include flapwise motion of the blades, teeter motion, and variable rotor speed. Options for the variable rotor speed include synchronous, induction, and constant-tip speed generator models with either start, stop, or normal operations. Verification is made by comparison with analytical solutions and mean and cyclic ESI-80 data. The Veers full-field turbulence model is used as a wind input for a synchronous and induction generator test case during normal operation. As a result of the comparison, it is concluded that the computer model can be used to predict accurately mean and cyclic loads with a turbulent wind input. 47 refs., 19 figs.

  11. An electric motor with magnetic bearings: A concept

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1973-01-01

    Because same magnetic flux is used to control rotor as to drive it, size, weight, and power required are minimized. Constant total current keeps motor torque invarient, and absence of mechanical bearings eliminates wear and reduces frictional power loss.

  12. Electric machine for hybrid motor vehicle

    DOEpatents

    Hsu, John Sheungchun

    2007-09-18

    A power system for a motor vehicle having an internal combustion engine and an electric machine is disclosed. The electric machine has a stator, a permanent magnet rotor, an uncluttered rotor spaced from the permanent magnet rotor, and at least one secondary core assembly. The power system also has a gearing arrangement for coupling the internal combustion engine to wheels on the vehicle thereby providing a means for the electric machine to both power assist and brake in relation to the output of the internal combustion engine.

  13. Method for assessing in-service motor efficiency and in-service motor/load efficiency

    DOEpatents

    Kueck, John D.; Otaduy, Pedro J.

    1997-01-01

    A method and apparatus for assessing the efficiency of an in-service motor. The operating characteristics of the in-service motor are remotely measured. The operating characteristics are then applied to an equivalent circuit for electrical motors. Finally the equivalent circuit is evaluated to determine the performance characteristics of said in-service motor. Based upon the evaluation an individual is able to determine the rotor speed, power output, efficiency, and toque of the in-service motor. Additionally, an individual is able to confirm the calculations by comparing measured values with values obtained as a result of the motor equivalent circuit evaluation.

  14. Integrated technology rotor/flight research rotor hub concept definition

    NASA Technical Reports Server (NTRS)

    Dixon, P. G. C.

    1983-01-01

    Two variations of the helicopter bearingless main rotor hub concept are proposed as bases for further development in the preliminary design phase of the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) program. This selection was the result of an evaluation of three bearingless hub concepts and two articulated hub concepts with elastomeric bearings. The characteristics of each concept were evaluated by means of simplified methodology. These characteristics included the assessment of stability, vulnerability, weight, drag, cost, stiffness, fatigue life, maintainability, and reliability.

  15. Blade lock for a rotor disk and rotor blade assembly

    NASA Technical Reports Server (NTRS)

    Moore, Jerry H. (Inventor)

    1992-01-01

    A rotor disk 18 and rotor blade 26 assembly is disclosed having a blade lock 66 which retains the rotor blade against axial movement in an axially extending blade retention slot 58. Various construction details are developed which shield the dead rim region D.sub.d and shift at least a portion of the loads associated with the locking device from the dead rim. In one detailed embodiment, a projection 68 from the live rim D.sub.1 of the disk 18 is adapted by slots 86 to receive blade locks 66.

  16. A traveling wave ultrasonic motor of high torque.

    PubMed

    Chen, Y; Liu, Q L; Zhou, T Y

    2006-12-22

    A traveling wave ultrasonic motor of high torque with a new configuration is proposed in this paper. In the new design, a part of the motor serves as the stator. The rotor is the vibrator consisting of a toothed metal ring with piezoelectric ceramic bonded, which generates ultrasonic vibration. The rotor is in contact with the shell of motor and is driven by the friction between the rotor and the stator. This configuration not only removes the rotor in a conventional type of traveling wave ultrasonic motor but also changes the interaction between the rotor and the stator of the motor so that it improves the output performance of the motor. Although an electric brush is added to the ultrasonic motor, it is easy to be fabricated because of the low speed of motor. The finite element method was used to compute the vibration modes of an ultrasonic motor with a diameter of 100mm to optimize the design of the motor. A 9th mode was chosen as the operation mode with a resonance frequency about 25 kHz. According to the design, a prototype was fabricated. Its performance was measured. The rotation speed-torque curves for various frequencies were obtained. The result shows that its stall torque is greater than 4 Nm within a range of 400 Hz. This ultrasonic motor was used to drive the window glass of a mobile car and the result was satisfactory. In the further the research on the friction material between the stator and the rotor is under way to improve the efficiency of the ultrasonic motor.

  17. Electric propulsion motor for marine vehicles

    SciTech Connect

    Dade, T.B.; Leiding, K.W.; Mongeau, P.P.; Piercey, M.S.

    1993-07-20

    An electric propulsion motor for marine vehicles is described comprising: a disk-shaped rotor and two coaxial disk-shaped stators, the rotor being separated from each of the stators in an axial direction by an air gap; the rotor including a plurality of permanent magnets that produce a first magnetic field; each stator comprising an armature winding that is connected to a source of electrical current to produce a second magnetic field, the first and second magnetic fields being capable of interacting to create an electromagnetic torque; means for coupling the rotor to a propeller shaft for transferring the torque from the rotor to the shaft, and means for detecting the angle of the shaft; a current control means for receiving a current control signal and for employing pulse width modulation to control the source of electrical current; the current control means including means for storing compensation information related to torque variations that are a function of shaft angle; the current control means further including means connected and responsive to the shaft angle detecting means for selecting the compensation information as a function of shaft angle and means for combining the compensation information with the current control signal to control the source of electrical current such that the torque variations that are a function of shaft angle are minimized; and wherein the means for coupling the rotor to the propeller shaft includes means within the motor for isolating the shaft from sound produced by the motor.

  18. NASA Open Rotor Noise Research

    NASA Technical Reports Server (NTRS)

    Envia, Ed

    2010-01-01

    Owing to their inherent fuel burn efficiency advantage compared with the current generation high bypass ratio turbofan engines, there is resurgent interest in developing open rotor propulsion systems for powering the next generation commercial aircraft. However, to make open rotor systems truly competitive, they must be made to be acoustically acceptable too. To address this challenge, NASA in collaboration with industry is exploring the design space for low-noise open rotor propulsion systems. The focus is on the system level assessment of the open rotors compared with other candidate concepts like the ultra high bypass ratio cycle engines. To that end there is an extensive research effort at NASA focused on component testing and diagnostics of the open rotor acoustic performance as well as assessment and improvement of open rotor noise prediction tools. In this presentation and overview of the current NASA research on open rotor noise will be provided. Two NASA projects, the Environmentally Responsible Aviation Project and the Subsonic Fixed Wing Project, have been funding this research effort.

  19. Gas turbine rotor straightening -- Case history

    SciTech Connect

    Mazur, Z.; Kubiak, J.; Villela, A.; Orozco, J.

    1999-11-01

    Due to catastrophic damage, the turbine-compressor rotor of a gas turbine has been bent 0.62 mm. The in-situ repair process of rotor straightening is fully described. The repair process included the design of special fixtures for placing the rotor vertically and then hydraulically tensioning the rotor bolts for discs disassembling and run-out check by a special rotary equipment. After the repair process the rotor run-out fell within the design limits. Finally the rotor was put back into service. The approach to the in-house repair of the rotor bend has been successful and can be widely recommended for users of turbomachinery.

  20. Control of a wind-driven self-excited induction generator water-pumping system for maximum utilization efficiency

    SciTech Connect

    Alghuwainem, S.M.

    1998-07-01

    This paper analyzes a stand-alone water-pumping system consisting of a motor-pump set supplied by a wind-driven self-excited induction generator. In order to achieve maximum utilization efficiency, the system designer is interested in optimally matching the system components together so that maximum energy available from the wind is absorbed and utilized all the time. Unfortunately, this optimal matching is speed-dependent and hence no single matching is valid for all wind speeds. Therefore the operating point of the system must vary with wind speed. In this paper, a control strategy is formulated which properly adjust the operating point of the system to coincide with the maximum power operating condition. The self-excited induction generator (SEIG) is basically an induction machine which is driven by a prime mover such as a wind turbine while a capacitor is connected across its stator terminals. The SEIG supplies an induction motor which is coupled to a water pump. The system need not operate continuously and water can be used directly for drinking and irrigation or it can be collected in a storage tank for later use. Due to the high cost of the wind turbine and equipment, the system designer is interested in maximizing the amount of pumped water per day. This can be achieved by proper selection and matching of the system components. However, proper matching of the system components together is not sufficient to guarantee maximum utilization since matching is dependent on wind speed. Therefore, certain system components must be controlled according to wind speed, such that matching is achieved all the time. This paper presents a control strategy to control the excitation capacitance of the induction generator such that its generated terminal voltage, which is applied to the induction motor, is kept constant as the rotor speed varies with wind speed.

  1. Wind turbine rotor aileron

    DOEpatents

    Coleman, Clint; Kurth, William T.

    1994-06-14

    A wind turbine has a rotor with at least one blade which has an aileron which is adjusted by an actuator. A hinge has two portions, one for mounting a stationary hinge arm to the blade, the other for coupling to the aileron actuator. Several types of hinges can be used, along with different actuators. The aileron is designed so that it has a constant chord with a number of identical sub-assemblies. The leading edge of the aileron has at least one curved portion so that the aileron does not vent over a certain range of angles, but vents if the position is outside the range. A cyclic actuator can be mounted to the aileron to adjust the position periodically. Generally, the aileron will be adjusted over a range related to the rotational position of the blade. A method for operating the cyclic assembly is also described.

  2. Control system for bearingless motor-generator

    NASA Technical Reports Server (NTRS)

    Kascak, Peter E. (Inventor); Jansen, Ralph H. (Inventor); Dever, Timothy P. (Inventor)

    2010-01-01

    A control system for an electromagnetic rotary drive for bearingless motor-generators comprises a winding configuration comprising a plurality of individual pole pairs through which phase current flows, each phase current producing both a lateral force and a torque. A motor-generator comprises a stator, a rotor supported for movement relative to the stator, and a control system. The motor-generator comprises a winding configuration supported by the stator. The winding configuration comprises at least three pole pairs through which phase current flows resulting in three three-phase systems. Each phase system has a first rotor reference frame axis current that produces a levitating force with no average torque and a second rotor reference frame axis current that produces torque.

  3. Control System for Bearingless Motor-generator

    NASA Technical Reports Server (NTRS)

    Kascak, Peter E. (Inventor); Jansen, Ralph H. (Inventor); Dever, Timothy P. (Inventor)

    2008-01-01

    A control system for an electromagnetic rotary drive for bearingless motor-generators comprises a winding configuration comprising a plurality of individual pole pairs through which phase current flows, each phase current producing both a lateral force and a torque. A motor-generator comprises a stator, a rotor supported for movement relative to the stator, and a control system. The motor-generator comprises a winding configuration supported by the stator. The winding configuration comprises at least three pole pairs through which phase current flows resulting in three three-phase systems. Each phase system has a first rotor reference frame axis current that produces a levitating force with no average torque and a second rotor reference frame axis current that produces torque.

  4. How induction generators work

    SciTech Connect

    Nailen, R.L.

    1980-06-01

    The operating principles of the induction generator, which is a standard squirrel cage motor in which the shaft is coupled to and driven by an engine or turbine at a rate above its synchronous speed and which, under these conditions, produces electrical power, are described. The advantages of induction generators, e.g., low cost, simplicity, frequency and voltage controlled by the utility system, no synchronizing controls needed, and the advantages of using small induction generators run by wind turbines, small gas turbines and in low head hydro plants are discussed. (LCL)

  5. Rotor component displacement measurement system

    DOEpatents

    Mercer, Gary D.; Li, Ming C.; Baum, Charles R.

    2003-05-27

    A measuring system for measuring axial displacement of a tube relative to an axially stationary component in a rotating rotor assembly includes at least one displacement sensor adapted to be located normal to a longitudinal axis of the tube; an insulated cable system adapted for passage through the rotor assembly; a rotatable proximitor module located axially beyond the rotor assembly to which the cables are connected; and a telemetry system operatively connected to the proximitor module for sampling signals from the proximitor module and forwarding data to a ground station.

  6. None of the Rotor Residues of F1-ATPase Are Essential for Torque Generation

    PubMed Central

    Chiwata, Ryohei; Kohori, Ayako; Kawakami, Tomonari; Shiroguchi, Katsuyuki; Furuike, Shou; Adachi, Kengo; Sutoh, Kazuo; Yoshida, Masasuke; Kinosita, Kazuhiko

    2014-01-01

    F1-ATPase is a powerful rotary molecular motor that can rotate an object several hundred times as large as the motor itself against the viscous friction of water. Forced reverse rotation has been shown to lead to ATP synthesis, implying that the mechanical work against the motor’s high torque can be converted into the chemical energy of ATP. The minimal composition of the motor protein is α3β3γ subunits, where the central rotor subunit γ turns inside a stator cylinder made of alternately arranged α3β3 subunits using the energy derived from ATP hydrolysis. The rotor consists of an axle, a coiled coil of the amino- and carboxyl-terminal α-helices of γ, which deeply penetrates the stator cylinder, and a globular protrusion that juts out from the stator. Previous work has shown that, for a thermophilic F1, significant portions of the axle can be truncated and the motor still rotates a submicron sized bead duplex, indicating generation of up to half the wild-type (WT) torque. Here, we inquire if any specific interactions between the stator and the rest of the rotor are needed for the generation of a sizable torque. We truncated the protruding portion of the rotor and replaced part of the remaining axle residues such that every residue of the rotor has been deleted or replaced in this or previous truncation mutants. This protrusionless construct showed an unloaded rotary speed about a quarter of the WT, and generated one-third to one-half of the WT torque. No residue-specific interactions are needed for this much performance. F1 is so designed that the basic rotor-stator interactions for torque generation and control of catalysis rely solely upon the shape and size of the rotor at very low resolution. Additional tailored interactions augment the torque to allow ATP synthesis under physiological conditions. PMID:24853745

  7. Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

    NASA Astrophysics Data System (ADS)

    Crapo, Alan D.; Lloyd, Jerry D.

    1991-03-01

    Two motors have been designed and built for use with high-temperature superconductor (HTSC) materials. They are a homopolar dc motor that uses HTSC field windings and a brushless dc motor that uses bulk HTSC materials to trap flux in steel rotor poles. The HTSC field windings of the homopolar dc motor are designed to operate at 1000 A/sq cm in a 0.010-T field. In order to maximize torque in the homopolar dc motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar dc motor has been tested while waiting for 575 A turn HTSC coils. The trapped flux brushless dc motor has been built and is ready to test melt textured bulk HTSC rings that are currently being prepared. The stator of the trapped flux motor will impress a magnetic field in the steel rotor poles with warm HTSC bulk rings. The rings are then cooled to 77 K to trap the flux in the rotor. The motor can then operate as a brushless dc motor.

  8. Rotor assembly for a gas turbine engine

    SciTech Connect

    Antonellis, S. M.; Breunig, R. D.

    1985-07-02

    A rotor assembly for a gas turbine engine is disclosed. The rotor assembly includes a pair of axially spaced apart rotor disks such as the rotor disks. An inner air seal extends axially between the adjacent rotor disks. A member extends axially between the disks to join the disks together and is attached to the inner air seal at a mid span location to restrain the seal against outward movement.

  9. Finite element modelling of a rotating piezoelectric ultrasonic motor.

    PubMed

    Frangi, A; Corigliano, A; Binci, M; Faure, P

    2005-10-01

    The evaluation of the performance of ultrasonic motors as a function of input parameters such as the driving frequency, voltage input and pre-load on the rotor is of key importance to their development and is here addressed by means of a finite element three-dimensional model. First the stator is simulated as a fully deformable elastic body and the travelling wave dynamics is accurately reproduced; secondly the interaction through contact between the stator and the rotor is accounted for by assuming that the rotor behaves as a rigid surface. Numerical results for the whole motor are finally compared to available experimental data.

  10. Torque for an Inertial Piezoelectric Rotary Motor

    PubMed Central

    Xing, Jichun

    2013-01-01

    For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor. PMID:24470794

  11. Bent shaft motor

    DOEpatents

    Benavides, Gilbert L.

    1998-01-01

    A nonelectromagnetic motor comprising a base, a bent shaft which is rotable relative to the base wherein the bent shaft comprises a straight portion aligned with a main axis and an offset portion that is offset with respect to the main axis; and a drive means for driving the offset portion of the bent shaft along a generally circular path in a plane perpendicular to the main axis to rotate the bent shaft. The bent shaft and drive means for driving the bent shaft can be selected from piezoelectric, magnetostrictive, rheological and shape memory alloys. The drive means of the nonelectromagnetic motor can additionally comprise a shell which shell surrounds and houses the bent shaft and precesses or gyrates which in turn causes the bent drive shaft to rotate. The nonelectromagnetic motor does not rely on friction for the application of torque upon a rotor.

  12. Bent shaft motor

    DOEpatents

    Benavides, G.L.

    1998-05-05

    A nonelectromagnetic motor comprising a base, a bent shaft which is rotatable relative to the base wherein the bent shaft comprises a straight portion aligned with a main axis and an offset portion that is offset with respect to the main axis; and a drive means for driving the offset portion of the bent shaft along a generally circular path in a plane perpendicular to the main axis to rotate the bent shaft. The bent shaft and drive means for driving the bent shaft can be selected from piezoelectric, magnetostrictive, rheological and shape memory alloys. The drive means of the nonelectromagnetic motor can additionally comprise a shell which shell surrounds and houses the bent shaft and precesses or gyrates which in turn causes the bent drive shaft to rotate. The nonelectromagnetic motor does not rely on friction for the application of torque upon a rotor. 11 figs.

  13. Advanced Ultra-High Speed Motor for Drilling

    SciTech Connect

    Impact Technologies LLC; University of Texas at Arlington

    2007-03-31

    Three (3) designs have been made for two sizes, 6.91 cm (2.72 inch) and 4.29 cm (1.69 inch) outer diameters, of a patented inverted configured Permanent Magnet Synchronous Machines (PMSM) electric motor specifically for drilling at ultra-high rotational speeds (10,000 rpm) and that can utilize advanced drilling methods. Benefits of these motors are stackable power sections, full control (speed and direction) of downhole motors, flow hydraulics independent of motor operation, application of advanced drilling methods (water jetting and abrasive slurry jetting), and the ability of signal/power electric wires through motor(s). Key features of the final designed motors are: fixed non-rotating shaft with stator coils attached; rotating housing with permanent magnet (PM) rotor attached; bit attached to rotating housing; internal channel(s) in a nonrotating shaft; electric components that are hydrostatically isolated from high internal pressure circulating fluids ('muds') by static metal to metal seals; liquid filled motor with smoothed features for minimized turbulence in the motor during operation; and new inverted coated metal-metal hydrodynamic bearings and seals. PMSM, Induction and Switched Reluctance Machines (SRM), all pulse modulated, were considered, but PMSM were determined to provide the highest power density for the shortest motors. Both radial and axial electric PMSM driven motors were designed with axial designs deemed more rugged for ultra-high speed, drilling applications. The 6.91 cm (2.72 inch) OD axial inverted motor can generate 4.18KW (5.61 Hp) power at 10,000 rpm with a 4 Nm (2.95 ft-lbs) of torque for every 30.48 cm (12 inches) of power section. The 6.91 cm (2.72 inch) OD radial inverted motor can generate 5.03 KW (6.74 Hp) with 4.8 Nm (3.54 ft-lb) torque at 10,000 rpm for every 30.48 cm (12 inches) of power section. The 4.29 cm (1.69 inch) OD radial inverted motor can generate 2.56 KW (3.43 Hp) power with 2.44 Nm (1.8 ft-lb) torque at full speed 10

  14. LAVA Applications to Open Rotors

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin C.; Housman, Jeff; Barad, Mike; Brehm, Christoph

    2015-01-01

    Outline: LAVA (Launch Ascent Vehicle Aerodynamics); Introduction; Acoustics Related Applications; LAVA Applications to Open Rotor; Structured Overset Grids; Cartesian Grid with Immersed Boundary; High Speed Case; High Speed Case with Plate Low Speed Case.

  15. Feedback Control of Rotor Overspeed

    NASA Technical Reports Server (NTRS)

    Churchill, G. B.

    1984-01-01

    Feedback system for automatically governing helicopter rotor speed promises to lessen pilot's workload, enhance maneuverability, and protect airframe. With suitable modifications, concept applied to control speed of electrical generators, automotive engines and other machinery.

  16. Soft hub for bearingless rotors

    NASA Technical Reports Server (NTRS)

    Dixon, Peter G. C.

    1991-01-01

    Soft hub concepts which allow the direct replacement of articulated rotor systems by bearingless types without any change in controllability or need for reinforcement to the drive shaft and/or transmission/fuselage attachments of the helicopter were studied. Two concepts were analyzed and confirmed for functional and structural feasibility against a design criteria and specifications established for this effort. Both systems are gimballed about a thrust carrying universal elastomeric bearing. One concept includes a set of composite flexures for drive torque transmittal from the shaft to the rotor, and another set (which is changeable) to impart hub tilting stiffness to the rotor system as required to meet the helicopter application. The second concept uses a composite bellows flexure to drive the rotor and to augment the hub stiffness provided by the elastomeric bearing. Each concept was assessed for weight, drag, ROM cost, and number of parts and compared with the production BO-105 hub.

  17. Examination of Sandwich-Type Multidegree-of-Freedom Spherical Ultrasonic Motor

    NASA Astrophysics Data System (ADS)

    Lu, Bo; Aoyagi, Manabu; Takano, Takehiro; Tamura, Hideki

    2010-07-01

    A sandwich-type multidegree-of-freedom (MDOF) spherical ultrasonic motor (SUSM) is newly proposed. The motor consists of a spherical rotor and two stator vibrators holding the rotor. This structure has both a rotor support and a preload mechanism. The stator excites five vibration modes, and the rotor can rotate on three axes. An experiment of a torque composition of two stators was carried out. The contact surface between the rotor and the stators forms a spherical surface. Moreover, a displacement magnification mechanism, which was used in the former model to rotate on the Z-axis, is no longer necessary. Hence the stator is simpler in construction than the former model. In this paper, we describe the construction and the operating principle of the MDOF ultrasonic motor, modal analysis results for the stator, and some measurement results from trial manufacturing. The miniaturization of the motor and increase in torque were successfully realized.

  18. Electrical stimulation during skill training with a therapeutic glove enhances the induction of cortical plasticity and has a positive effect on motor memory.

    PubMed

    Christova, Monica; Rafolt, Dietmar; Golaszewski, Stefan; Nardone, Raffaele; Gallasch, Eugen

    2014-08-15

    To examine whether afferent stimulation of hand muscles has a facilitating effect on motor performance, learning and cortical excitability, healthy subjects were trained on the grooved pegboard test (GTP) while wearing a mesh glove (MG) with incorporated electrical stimulation. Three study groups (n=12) were compared in a between subjects design, the bare handed (BH), gloved (MG) and gloved with electrical stimulation (MGS) groups. Motor performance was assessed by the GPT completion time across 4 training blocks, and further one block was retested 7 days later to determine the off-line effects. On-line learning was obtained by normalizing the completion time values to the first training block, and off-line learning was obtained by normalizing the retest values to the last training block. Cortical excitability was assessed via single and paired-pulse transcranial magnetic stimulation (TMS) at pre-training, post-training and 30 min post-training. Motor evoked potential recruitment curve, short-latency intracortical inhibition and intracortical facilitation were estimated from the TMS assessments. Motor performance across all 4 training blocks was poor in the MG and MGS groups, while on-line learning was not affected by wearing the glove or by afferent stimulation. However, off-line learning, tested 7 days after training, was improved in the MGS group compared to the MG group. In addition, post-training corticospinal excitability was increased in the MGS group. It can be concluded that afferent stimulation improves off-line learning and thus has a positive effect on motor memory, likely due to LTP-like cortical plasticity in the consolidation phase.

  19. Analysis and Design Considerations of a High-Power Density, Dual Air Gap, Axial-Field Brushless, Permanent Magnet Motor.

    NASA Astrophysics Data System (ADS)

    Cho, Chahee Peter

    1995-01-01

    Until recently, brush dc motors have been the dominant drive system because they provide easily controlled motor speed over a wide range, rapid acceleration and deceleration, convenient control of position, and lower product cost. Despite these capabilities, the brush dc motor configuration does not satisfy the design requirements for the U.S. Navy's underwater propulsion applications. Technical advances in rare-earth permanent magnet materials, in high-power semiconductor transistor technology, and in various rotor position-sensing devices have made using brushless permanent magnet motors a viable alternative. This research investigates brushless permanent magnet motor technology, studying the merits of dual-air gap, axial -field, brushless, permanent magnet motor configuration in terms of power density, efficiency, and noise/vibration levels. Because the design objectives for underwater motor applications include high-power density, high-performance, and low-noise/vibration, the traditional, simplified equivalent circuit analysis methods to assist in meeting these goals were inadequate. This study presents the development and verification of detailed finite element analysis (FEA) models and lumped parameter circuit models that can calculate back electromotive force waveforms, inductance, cogging torque, energized torque, and eddy current power losses. It is the first thorough quantification of dual air-gap, axial -field, brushless, permanent magnet motor parameters and performance characteristics. The new methodology introduced in this research not only facilitates the design process of an axial field, brushless, permanent magnet motor but reinforces the idea that the high-power density, high-efficiency, and low-noise/vibration motor is attainable.

  20. An online technique for condition monitoring the induction generators used in wind and marine turbines

    NASA Astrophysics Data System (ADS)

    Yang, Wenxian; Tavner, P. J.; Court, R.

    2013-07-01

    Induction generators have been successfully applied to a variety of industries. However, their operation and maintenance in renewable wind and marine energy industries still face challenges due to harsh environments, limited access to site and relevant reliability issues. Hence, further enhancing their condition monitoring is regarded as one of the essential measures for improving their availability. To date, much effort has been made to monitor induction motors, which can be equally applied to monitoring induction generators. However, the achieved techniques still have constrains in particular when dealing with the condition monitoring problems in wind and marine turbine generators. For example, physical measurements of partial discharge, noise and temperature have been widely applied to monitoring induction machinery. They are simple and cost-effective, but unable to be used for fault diagnosis. The spectral analysis of vibration and stator current signals is also a mature technique popularly used in motor/generator condition monitoring practice. However, it often requires sufficient expertise for data interpretation, and significant pre-knowledge about the machines and their components. In particular in renewable wind and marine industries, the condition monitoring results are usually coupled with load variations, which further increases the difficulty of obtaining a reliable condition monitoring result. In view of these issues, a new condition monitoring technique is developed in this paper dedicated for wind and marine turbine generators. It is simple, informative and less load-dependent thus more reliable to deal with the online motor/generator condition monitoring problems under varying loading conditions. The technique has been verified through both simulated and practical experiments. It has been shown that with the aid of the proposed technique, not only the electrical faults but also the shaft unbalance occurring in the generator become detectable

  1. Hermatically sealed motor blower unit with stator inside hollow armature

    DOEpatents

    Donelian, Khatchik O.

    1976-01-20

    13. A hermetically sealed motor blower unit comprising, in combination, a sealed housing having a thrust plate mounted therein and having a re-entrant wall forming a central cavity in said housing, a rotor within said housing, said rotor comprising an impeller, a hollow shaft embracing said cavity and a thrust collar adapted to cooperate with said thrust plate to support the axial thrust of said shaft, one or more journal bearings within said housing for supporting the radial load of said shaft and electric motor means for rotating said rotor, said motor means comprising a motor-stator located within said cavity and adapted to cooperate through a portion of said re-entrant wall with a motor-rotor mounted within said hollow shaft, the portion of said re-entrant wall located between said motor-stator and said motor-rotor being made relatively thin to reduce electrical losses, the bearing surfaces of said thrust plate, thrust collar and journal bearings being in communication with the discharge of said impeller, whereby fluid pumped by said impeller can flow directly to said bearing surfaces to lubricate them.

  2. Macroscopic balance model for wave rotors

    NASA Technical Reports Server (NTRS)

    Welch, Gerard E.

    1996-01-01

    A mathematical model for multi-port wave rotors is described. The wave processes that effect energy exchange within the rotor passage are modeled using one-dimensional gas dynamics. Macroscopic mass and energy balances relate volume-averaged thermodynamic properties in the rotor passage control volume to the mass, momentum, and energy fluxes at the ports. Loss models account for entropy production in boundary layers and in separating flows caused by blade-blockage, incidence, and gradual opening and closing of rotor passages. The mathematical model provides a basis for predicting design-point wave rotor performance, port timing, and machine size. Model predictions are evaluated through comparisons with CFD calculations and three-port wave rotor experimental data. A four-port wave rotor design example is provided to demonstrate model applicability. The modeling approach is amenable to wave rotor optimization studies and rapid assessment of the trade-offs associated with integrating wave rotors into gas turbine engine systems.

  3. An Induction Motor Drive System Based on the Back-To-Back Connection of Two Five-Level Diode-Clamped PWM Converters

    NASA Astrophysics Data System (ADS)

    Kondo, Yosuke; Natchpong, Hatti; Akagi, Hirofumi

    This paper discusses a 6.6-kV transformerless motor drive system based on the back-to-back connection of two five-level diode-clamped PWM converters. In addition, this paper designs, constructs and experimentally tests a down-scaled model rated at 200V and 5.5kW. This system consist of the two five-level converters, a common dc-link, and voltage-balancing circuits using two bi-directional buck-boost choppers. Experimental results obtained from the down-scaled model verify the validity of the system design, giving promise of the viability of the 6.6-kV transformerless motor drive system.

  4. Prediction of torque and inductance displacement characteristics of asymmetrically slotted variable-reluctance motors using a simplified model for numerical field solution

    SciTech Connect

    Ertan, H.B.

    1999-09-01

    For prediction of static and dynamic performance of doubly-salient motors, it is essential to know their flux linkage-position-excitation characteristics and also the static torque characteristics. At the design stage determination of these characteristics presents difficulties because of highly nonlinear behavior of the magnetic circuit. It is possible to use numerical field solution of the complete motor to obtain this information. This, however, requires expertise on a professional program and may be expensive if used to search for the best design. This paper shows that a reduced model can be used to obtain the desired information accurately. It is also shown that in fact obtaining field solutions just for a pair of teeth is enough for accurately predicting the flux linkage and torque characteristics of a motor. The approach introduced here makes possible searching for an optimum design (even on a PC) for maximizing average torque or reducing noise and vibration problems, since the effort for producing the model and computation time are greatly reduced.

  5. Magnetically suspended rotary blood pump with radial type combined motor-bearing.

    PubMed

    Masuzawa, T; Kita, T; Matsuda, K; Okada, Y

    2000-06-01

    A magnetically suspended centrifugal blood pump is being developed with a combined motor-bearing for long-term ventricular assist systems. The combined motor-bearing actively suspends a rotor in a radial direction to deal with radial force unbalance in the pump and rotates the rotor by using the electric magnetic field. Therefore, the pump has no mechanical parts such as bearings of the motor and has a long lifetime. The developed pump consists of a thin rotor with a semi open-type 6 vane impeller and a stator to suspend and rotate the rotor. The rotor has 4-pole permanent magnets on the circumferential surface. The outer diameter and the thickness of the rotor are 60 mm and 8 mm, respectively. Axial movement and tilt of the rotor are restricted by passive stability based on the thin rotor structure. Radial movements of the rotor, such as levitation in radial direction and rotation, are controlled actively by using electric magnets of the stator. The electric magnet coils to produce levitation and rotation forces are constructed on the periphery stator. The p +/- 2-pole algorithm and the synchronous motor mechanism are adopted to levitate and rotate the rotor. The radial gap between the rotor and the stator is 1 mm. A closed-loop circuit filled with water was connected to the developed pump to examine the basic performance of the pump and the magnetic suspension system. Maximum rotational speed, flow rate, and head were 2,800 rpm, 11 L/min, and 270 mm Hg, respectively. The rotor with the impeller could be suspended completely during the entire pumping process. We conclude the pump with the combined motor-bearing has sufficient performance for the blood pump.

  6. System for Controlling a Magnetically Levitated Rotor

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R. (Inventor)

    2006-01-01

    In a rotor assembly having a rotor supported for rotation by magnetic bearings, a processor controlled by software or firmware controls the generation of force vectors that position the rotor relative to its bearings in a "bounce" mode in which the rotor axis is displaced from the principal axis defined between the bearings and a "tilt" mode in which the rotor axis is tilted or inclined relative to the principal axis. Waveform driven perturbations are introduced to generate force vectors that excite the rotor in either the "bounce" or "tilt" modes.

  7. Research investigation of helicopter main rotor/tail rotor interaction noise

    NASA Technical Reports Server (NTRS)

    Fitzgerald, J.; Kohlhepp, F.

    1988-01-01

    Acoustic measurements were obtained in a Langley 14 x 22 foot Subsonic Wind Tunnel to study the aeroacoustic interaction of 1/5th scale main rotor, tail rotor, and fuselage models. An extensive aeroacoustic data base was acquired for main rotor, tail rotor, fuselage aerodynamic interaction for moderate forward speed flight conditions. The details of the rotor models, experimental design and procedure, aerodynamic and acoustic data acquisition and reduction are presented. The model was initially operated in trim for selected fuselage angle of attack, main rotor tip-path-plane angle, and main rotor thrust combinations. The effects of repositioning the tail rotor in the main rotor wake and the corresponding tail rotor countertorque requirements were determined. Each rotor was subsequently tested in isolation at the thrust and angle of attack combinations for trim. The acoustic data indicated that the noise was primarily dominated by the main rotor, especially for moderate speed main rotor blade-vortex interaction conditions. The tail rotor noise increased when the main rotor was removed indicating that tail rotor inflow was improved with the main rotor present.

  8. Mountain Plains Learning Experience Guide: Electric Motor Repair.

    ERIC Educational Resources Information Center

    Ziller, T.

    This Electric Motor Repair Course is designed to provide the student with practical information for winding, repairing, and troubleshooting alternating current and direct current motors, and controllers. The course is comprised of eight units: (1) Electric Motor Fundamentals, (2) Rewinding, (3) Split-phase Induction Motors, (4) Capacitor Motors,…

  9. A novel self-shielding permanent-magnet rotor assembly

    NASA Astrophysics Data System (ADS)

    Potenziani, E., II; Leupold, H. A.; Basarab, D. J.

    1988-11-01

    The use of permanent magnets in brushless motors and generators is highly desirable in that they have great potential for reducing weight and increasing efficiency. A self-shielding cylindrical permanent-magnet assembly has been designed and was found to produce high fields at the outer magnet surface and very little flux leakage into the interior rotor space. Construction of this assembly is simplified because it is composed of magnets of simple triangular cross sections, which have only four distinct orientations. The self-shielding nature of the design obviates any need for ferromagnetic material for flux shaping or shielding, thus simplifying greatly the mathematical analysis of the design and reducing its weight and bulk. Finite element methods are used to analyze a hypothetical permanent-magnet rotor assembly with regard to various design parameters.

  10. An experimental study of rotor-filter pump performance

    SciTech Connect

    Marshek, K.M.; Naja, M.R.

    1982-09-01

    The performance of a rotor-filter pump has been studied experimentally. To develop an understanding of pump performance, and in particular to discern the mechanism of hydraulic pulsing, flow visualization in the rotor, vibration analyses of the pump, frequency analysis of the pump hydraulic pressure pulsation, and analyses of flow characteristics for different pick-up tubes in combination with different impellers and cover plates were conducted. The frequencies of the pump's hydraulic pulsation is shown to be a function of the number of pick-up arms and the motor speed. The pump vibration and its pulsation amplitude were reduced by increasing the number of pick-up arms or by adding a radial impeller. These actions increased the lowest frequency of pulsation and decreased the chance of excitation of the pump system parts.

  11. Turbomachinery rotor support with damping

    NASA Technical Reports Server (NTRS)

    Vonpragenau, George L. (Inventor)

    1990-01-01

    Damping seals, damping bearings, and a support sleeve are presented for the ball bearings of a high speed rotor. The ball bearings consist of a duplex set having the outer races packaged tightly within the sleeve while the sleeve provides a gap with a support member so that the bearings may float with the sleeve. The sleeve has a web extending radially between the pair of outer races and acts in conjunction with one or more springs to apply an axial preload to the outer races. The sleeves have a series of slits which provide the sleeve with a spring-like quality so that the spring acts to center the rotor upon which the bearings are mounted during start up and shut down. A damping seal or a damping bearing may be used in conjunction with the ball bearings and supporting sleeve, the damping seal and damping bearing having rotor portions including rigid outer surfaces mounted within the bore of a stator portion having triangular shaped pockets on the surface facing the rotor. Axial gates are provided between adjacent pockets in sections of the stator permitting fluid to flow with less resistance axially relative to the flow of fluids circumferentially between the rotor and the stator.

  12. Rotor assembly and assay method

    DOEpatents

    Burtis, Carl A.; Johnson, Wayne F.; Walker, William A.

    1993-01-01

    A rotor assembly for carrying out an assay includes a rotor body which is rotatable about an axis of rotation, and has a central chamber and first, second, third, fourth, fifth, and sixth chambers which are in communication with and radiate from the central chamber. The rotor assembly further includes a shuttle which is movable through the central chamber and insertable into any of the chambers, the shuttle including a reaction cup carrying an immobilized antigen or an antibody for transport among the chambers. A method for carrying out an assay using the rotor assembly includes moving the reaction cup among the six chambers by passing the cup through the central chamber between centrifugation steps in order to perform the steps of: separating plasma from blood cells, binding plasma antibody or antigen, washing, drying, binding enzyme conjugate, reacting with enzyme substrate and optically comparing the resulting reaction product with unreacted enzyme substrate solution. The movement of the reaction cup can be provided by attaching a magnet to the reaction cup and supplying a moving magnetic field to the rotor.

  13. Rotor assembly and assay method

    DOEpatents

    Burtis, C.A.; Johnson, W.F.; Walker, W.A.

    1993-09-07

    A rotor assembly for carrying out an assay includes a rotor body which is rotatable about an axis of rotation, and has a central chamber and first, second, third, fourth, fifth, and sixth chambers which are in communication with and radiate from the central chamber. The rotor assembly further includes a shuttle which is movable through the central chamber and insertable into any of the chambers, the shuttle including a reaction cup carrying an immobilized antigen or an antibody for transport among the chambers. A method for carrying out an assay using the rotor assembly includes moving the reaction cup among the six chambers by passing the cup through the central chamber between centrifugation steps in order to perform the steps of: separating plasma from blood cells, binding plasma antibody or antigen, washing, drying, binding enzyme conjugate, reacting with enzyme substrate and optically comparing the resulting reaction product with unreacted enzyme substrate solution. The movement of the reaction cup can be provided by attaching a magnet to the reaction cup and supplying a moving magnetic field to the rotor. 34 figures.

  14. Modeling an electric motor in 1-D

    NASA Technical Reports Server (NTRS)

    Butler, Thomas G.

    1991-01-01

    Quite often the dynamicist will be faced with having an electric drive motor as a link in the elastic path of a structure such that the motor's characteristics must be taken into account to properly represent the dynamics of the primary structure. He does not want to model it so accurately that he could get detailed stress and displacements in the motor proper, but just sufficiently to represent its inertia loading and elastic behavior from its mounting bolts to its drive coupling. Described here is how the rotor and stator of such a motor can be adequately modeled as a colinear pair of beams.

  15. Unidirectional rotary motion in achiral molecular motors.

    PubMed

    Kistemaker, Jos C M; Štacko, Peter; Visser, Johan; Feringa, Ben L

    2015-11-01

    Control of the direction of motion is an essential feature of biological rotary motors and results from the intrinsic chirality of the amino acids from which the motors are made. In synthetic autonomous light-driven rotary motors, point chirality is transferred to helical chirality, and this governs their unidirectional rotation. However, achieving directional rotary motion in an achiral molecular system in an autonomous fashion remains a fundamental challenge. Here, we report an achiral molecular motor in which the presence of a pseudo-asymmetric carbon atom proved to be sufficient for exclusive autonomous disrotary motion of two appended rotor moieties. Isomerization around the two double bonds enables both rotors to move in the same direction with respect to their surroundings--like wheels on an axle--demonstrating that autonomous unidirectional rotary motion can be achieved in a symmetric system.

  16. Products of motor burnout. Final report

    SciTech Connect

    Hawley-Fedder, R.; Goerz, D.; Koester, C.; Wilson, M.

    1996-03-30

    The Montreal Protocol of 1987 effectively banned a long list of chlorofluorocarbons (CFCs) traditionally used in air conditioning and refrigeration applications. The refrigeration and air conditioning industries have responded by developing and testing new, alternative refrigerants that are less damaging to the atmosphere upon release. Despite a reputation for quality and reliability, air conditioning systems do occasionally fail. One of the more common failure modes in a hermetic system is a motor burnout. Motor burnouts can occur by various mechanisms. One of the most common scenarios is a locked motor rotor, which may result from a damaged bearing. The resulting electrical motor burnout is caused by overheating of the locked rotor and subsequent failure of the insulation. This is primarily a thermal breakdown process.

  17. Unidirectional rotary motion in achiral molecular motors

    NASA Astrophysics Data System (ADS)

    Kistemaker, Jos C. M.; Štacko, Peter; Visser, Johan; Feringa, Ben L.

    2015-11-01

    Control of the direction of motion is an essential feature of biological rotary motors and results from the intrinsic chirality of the amino acids from which the motors are made. In synthetic autonomous light-driven rotary motors, point chirality is transferred to helical chirality, and this governs their unidirectional rotation. However, achieving directional rotary motion in an achiral molecular system in an autonomous fashion remains a fundamental challenge. Here, we report an achiral molecular motor in which the presence of a pseudo-asymmetric carbon atom proved to be sufficient for exclusive autonomous disrotary motion of two appended rotor moieties. Isomerization around the two double bonds enables both rotors to move in the same direction with respect to their surroundings—like wheels on an axle—demonstrating that autonomous unidirectional rotary motion can be achieved in a symmetric system.

  18. Rotor-to-stator Partial Rubbing and Its Effects on Rotor Dynamic Response

    NASA Technical Reports Server (NTRS)

    Muszynska, Agnes; Franklin, Wesley D.; Hayashida, Robert D.

    1991-01-01

    Results from experimental and analytical studies on rotor to stationary element partial rubbings at several locations and their effects on rotor dynamic responses are presented. The mathematical model of a rubbing rotor is given. The computer program provides numerical results which agree with experimentally obtained rotor responses.

  19. Rotor/Wing Interactions in Hover

    NASA Technical Reports Server (NTRS)

    Young, Larry A.; Derby, Michael R.

    2002-01-01

    Hover predictions of tiltrotor aircraft are hampered by the lack of accurate and computationally efficient models for rotor/wing interactional aerodynamics. This paper summarizes the development of an approximate, potential flow solution for the rotor-on-rotor and wing-on-rotor interactions. This analysis is based on actuator disk and vortex theory and the method of images. The analysis is applicable for out-of-ground-effect predictions. The analysis is particularly suited for aircraft preliminary design studies. Flow field predictions from this simple analytical model are validated against experimental data from previous studies. The paper concludes with an analytical assessment of the influence of rotor-on-rotor and wing-on-rotor interactions. This assessment examines the effect of rotor-to-wing offset distance, wing sweep, wing span, and flaperon incidence angle on tiltrotor inflow and performance.

  20. Open Rotor: New Option for Jet Engines

    NASA Video Gallery

    NASA's Dale Van Zante describes how the open rotor propulsion system will be tested in a wind tunnel at NASA's Glenn Research Center. Open rotor aircraft engines use high-speed propellers and are c...

  1. Rotor for centrifugal fast analyzers

    DOEpatents

    Lee, N.E.

    1984-01-01

    The invention is an improved photometric analyzer of the rotary cuvette type, the analyzer incorporating a multicuvette rotor of novel design. The rotor (a) is leaktight, (b) permits operation in the 90/sup 0/ and 180/sup 0/ excitation modes, (c) is compatible with extensively used Centrifugal Fast Analyzers, and (d) can be used thousands of times. The rotor includes an assembly comprising a top plate, a bottom plate, and a central plate, the rim of the central plate being formed with circumferentially spaced indentations. A uv-transmitting ring is sealably affixed to the indented rim to define with the indentations an array of cuvettes. The ring serves both as a sealing means and an end window for the cuvettes.

  2. Rotor for centrifugal fast analyzers

    DOEpatents

    Lee, Norman E.

    1985-01-01

    The invention is an improved photometric analyzer of the rotary cuvette type, the analyzer incorporating a multicuvette rotor of novel design. The rotor (a) is leaktight, (b) permits operation in the 90.degree. and 180.degree. excitation modes, (c) is compatible with extensively used Centrifugal Fast Analyzers, and (d) can be used thousands of times. The rotor includes an assembly comprising a top plate, a bottom plate, and a central plate, the rim of the central plate being formed with circumferentially spaced indentations. A UV-transmitting ring is sealably affixed to the indented rim to define with the indentations an array of cuvettes. The ring serves both as a sealing means and an end window for the cuvettes.

  3. Turbomachine rotor with improved cooling

    DOEpatents

    Hultgren, Kent Goran; McLaurin, Leroy Dixon; Bertsch, Oran Leroy; Lowe, Perry Eugene

    1998-01-01

    A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn.

  4. Turbomachine rotor with improved cooling

    DOEpatents

    Hultgren, K.G.; McLaurin, L.D.; Bertsch, O.L.; Lowe, P.E.

    1998-05-26

    A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn. 5 figs.

  5. On Cup Anemometer Rotor Aerodynamics

    PubMed Central

    Pindado, Santiago; Pérez, Javier; Avila-Sanchez, Sergio

    2012-01-01

    The influence of anemometer rotor shape parameters, such as the cups' front area or their center rotation radius on the anemometer's performance was analyzed. This analysis was based on calibrations performed on two different anemometers (one based on magnet system output signal, and the other one based on an opto-electronic system output signal), tested with 21 different rotors. The results were compared to the ones resulting from classical analytical models. The results clearly showed a linear dependency of both calibration constants, the slope and the offset, on the cups' center rotation radius, the influence of the front area of the cups also being observed. The analytical model of Kondo et al. was proved to be accurate if it is based on precise data related to the aerodynamic behavior of a rotor's cup. PMID:22778638

  6. On cup anemometer rotor aerodynamics.

    PubMed

    Pindado, Santiago; Pérez, Javier; Avila-Sanchez, Sergio

    2012-01-01

    The influence of anemometer rotor shape parameters, such as the cups' front area or their center rotation radius on the anemometer's performance was analyzed. This analysis was based on calibrations performed on two different anemometers (one based on magnet system output signal, and the other one based on an opto-electronic system output signal), tested with 21 different rotors. The results were compared to the ones resulting from classical analytical models. The results clearly showed a linear dependency of both calibration constants, the slope and the offset, on the cups' center rotation radius, the influence of the front area of the cups also being observed. The analytical model of Kondo et al. was proved to be accurate if it is based on precise data related to the aerodynamic behavior of a rotor's cup.

  7. A brushless dc spin motor for momentum exchange altitude control

    NASA Technical Reports Server (NTRS)

    Stern, D.; Rosenlieb, J. W.

    1972-01-01

    Brushless dc spin motor is designed to use Hall effect probes as means of revolving rotor position and controlling motor winding currents. This results in 3 to 1 reduction in watt-hours required for wheel acceleration, a 2 to 1 reduction in power to run wheel, and a 10 to 1 reduction in the electronics size and weight.

  8. Wave Rotor Research and Technology Development

    NASA Technical Reports Server (NTRS)

    Welch, Gerard E.

    1998-01-01

    Wave rotor technology offers the potential to increase the performance of gas turbine engines significantly, within the constraints imposed by current material temperature limits. The wave rotor research at the NASA Lewis Research Center is a three-element effort: 1) Development of design and analysis tools to accurately predict the performance of wave rotor components; 2) Experiments to characterize component performance; 3) System integration studies to evaluate the effect of wave rotor topping on the gas turbine engine system.

  9. Using a micromachined magnetostatic relay in commutating a DC motor

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Wright, John A. (Inventor); Lilienthal, Gerald (Inventor)

    2004-01-01

    A DC motor is commutated by rotating a magnetic rotor to induce a magnetic field in at least one magnetostatic relay in the motor. Each relay is activated in response to the magnetic field to deliver power to at least one corresponding winding connected to the relay. In some cases, each relay delivers power first through a corresponding primary winding and then through a corresponding secondary winding to a common node. Specific examples include a four-pole, three-phase motor in which each relay is activated four times during one rotation of the magnetic rotor.

  10. A DIRECT CURRENT MOTOR WITH NO CONTACTS AND A TRANSISTOR COMMUTATOR.

    DTIC Science & Technology

    dc motor of low power in which the collector is replaced by a transistor commutator controlled by a transformer sensor of the position of the rotor with respect to the stator. The rotor of the motor consists of a 2-pole permanent magnet. The transistor commutator of the motor may be used as a power amplifier. Control of motor speed is easily accomplished by means of modulating the input signals to the commutator. The motor is controlled by signals of low power which makes it possible to use it in automatic control systems without the use of very powerful additional

  11. Small dc motor for producing motion in a cryogenic environment, and a method for monitoring its orientation

    NASA Astrophysics Data System (ADS)

    Walker, I. R.

    1993-03-01

    In the field of condensed matter physics, it is frequently necessary to produce motion at low temperatures. While this can often be done using a mechanical linkage which connects the cryogenic and ambient environments, space constraints sometimes render such a solution impractical. The following paper describes a miniature dc electric motor which can be used to produce motion under these conditions, and also presents a novel scheme for monitoring its position. The motor is a skew-wound ironless device with a coaxial gearhead, and is capable of operating at a temperature of 4 K, in a vacuum, and in a magnetic field of several hundred gauss. The position monitoring arrangement requires no modifications to the motor or the addition of extra hardware, such as rotary encoders or potentiometers. Based on the angular dependence of the rotor inductance, it has been found to work with a number of different motors of the skew-wound ironless type, both at room temperature and at 4°. Provisions have been made to allow the motor and position monitor to be operated by computer control. The author anticipates that they will find applications in other areas where motion is needed and space is at a premium.

  12. Filter type rotor for multistation photometer

    DOEpatents

    Shumate, II, Starling E.

    1977-07-12

    A filter type rotor for a multistation photometer is provided. The rotor design combines the principle of cross-flow filtration with centrifugal sedimentation so that these occur simultaneously as a first stage of processing for suspension type fluids in an analytical type instrument. The rotor is particularly useful in whole-blood analysis.

  13. Special-Purpose High-Torque Permanent-Magnet Motors

    NASA Technical Reports Server (NTRS)

    Doane, George B., III

    1995-01-01

    Permanent-magnet brushless motors that must provide high commanded torques and satisfy unusual heat-removal requirement are developed. Intended for use as thrust-vector-control actuators in large rocket engines. Techniques and concepts used to design improved motors for special terrestrial applications. Conceptual motor design calls for use of rotor containing latest high-energy-product rare-earth permanent magnets so that motor produces required torque while drawing smallest possible currents from power supply. Torque generated by electromagnetic interaction between stator and permanent magnets in rotor when associated electronic circuits applied appropriately temporally and spatially phased currents to stator windings. Phase relationships needed to produce commanded torque computed in response to torque command and to electronically sensed angular position of rotor relative to stator.

  14. Development of a prototype magnetically suspended rotor ventricular assist device.

    PubMed

    Bearnson, G B; Maslen, E H; Olsen, D B; Allaire, P E; Khanwilkar, P S; Long, J W; Kim, H C

    1996-01-01

    A continuous flow centrifugal blood pump with magnetically suspended impeller has been designed, constructed, and tested. The system can be functionally divided into three subsystem designs: 1) centrifugal pump and flow paths, 2) magnetic bearings, and 3) brushless DC motor. The centrifugal pump is a Francis vane type design with a designed operating point of 6 L/min flow and 100 mmHg pressure rise at 2,300 RPM. Peak hydraulic efficiency is over 50%. The magnetic bearing system is an all active design with five axes of control. Rotor position sensors were developed as part of the system to provide feedback to a proportional-integral-derivative controller. The motor is a sensorless brushless DC motor. Back electromotive force voltage generated by the motor is used to provide commutation for the motor. No slots are employed in the motor design in order to reduce the radial force that the bearings must generate. Tests pumping blood in vitro were very encouraging; an index of hemolysis of 0.0086 +/- 0.0012 was measured. Further design refinement is needed to reduce power dissipation and size of the device. The concept of using magnetic bearings in a blood pump shows promise in a long-term implantable blood pump.

  15. Induction of Neuron-Specific Degradation of Coenzyme A Models Pantothenate Kinase-Associated Neurodegeneration by Reducing Motor Coordination in Mice

    PubMed Central

    Shumar, Stephanie A.; Fagone, Paolo; Alfonso-Pecchio, Adolfo; Gray, John T.; Rehg, Jerold E.; Jackowski, Suzanne; Leonardi, Roberta

    2015-01-01

    Background Pantothenate kinase-associated neurodegeneration, PKAN, is an inherited disorder characterized by progressive impairment in motor coordination and caused by mutations in PANK2, a human gene that encodes one of four pantothenate kinase (PanK) isoforms. PanK initiates the synthesis of coenzyme A (CoA), an essential cofactor that plays a key role in energy metabolism and lipid synthesis. Most of the mutations in PANK2 reduce or abolish the activity of the enzyme. This evidence has led to the hypothesis that lower CoA might be the underlying cause of the neurodegeneration in PKAN patients; however, no mouse model of the disease is currently available to investigate the connection between neuronal CoA levels and neurodegeneration. Indeed, genetic and/or dietary manipulations aimed at reducing whole-body CoA synthesis have not produced a desirable PKAN model, and this has greatly hindered the discovery of a treatment for the disease. Objective, Methods, Results and Conclusions Cellular CoA levels are tightly regulated by a balance between synthesis and degradation. CoA degradation is catalyzed by two peroxisomal nudix hydrolases, Nudt7 and Nudt19. In this study we sought to reduce neuronal CoA in mice through the alternative approach of increasing Nudt7-mediated CoA degradation. This was achieved by combining the use of an adeno-associated virus-based expression system with the synapsin (Syn) promoter. We show that mice with neuronal overexpression of a cytosolic version of Nudt7 (scAAV9-Syn-Nudt7cyt) exhibit a significant decrease in brain CoA levels in conjunction with a reduction in motor coordination. These results strongly support the existence of a link between CoA levels and neuronal function and show that scAAV9-Syn-Nudt7cyt mice can be used to model PKAN. PMID:26052948

  16. Ironless armature torque motor

    NASA Technical Reports Server (NTRS)

    Fisher, R. L.

    1972-01-01

    Four iron-less armature torque motors, four Hall device position sensor assemblies, and two test fixtures were fabricated. The design approach utilized samarium cobalt permanent magnets, a large airgap, and a three-phase winding in a stationary ironless armature. Hall devices were employed to sense rotor position. An ironless armature torque motor having an outer diameter of 4.25 inches was developed to produce a torque constant of 65 ounce-inches per ampere with a resistance of 20.5 ohms. The total weight, including structural elements, was 1.58 pounds. Test results indicated that all specifications were met except for generated voltage waveform. It is recommended that investigations be made concerning the generated voltage waveform to determine if it may be improved.

  17. Reducing current reversal time in electric motor control

    DOEpatents

    Bredemann, Michael V

    2014-11-04

    The time required to reverse current flow in an electric motor is reduced by exploiting inductive current that persists in the motor when power is temporarily removed. Energy associated with this inductive current is used to initiate reverse current flow in the motor.

  18. System and method to determine electric motor efficiency using an equivalent circuit

    DOEpatents

    Lu, Bin; Habetler, Thomas G.

    2011-06-07

    A system and method for determining electric motor efficiency includes a monitoring system having a processor programmed to determine efficiency of an electric motor under load while the electric motor is online. The determination of motor efficiency is independent of a rotor speed measurement. Further, the efficiency is based on a determination of stator winding resistance, an input voltage, and an input current. The determination of the stator winding resistance occurs while the electric motor under load is online.

  19. System and method to determine electric motor efficiency using an equivalent circuit

    DOEpatents

    Lu, Bin; Habetler, Thomas G.

    2015-10-27

    A system and method for determining electric motor efficiency includes a monitoring system having a processor programmed to determine efficiency of an electric motor under load while the electric motor is online. The determination of motor efficiency is independent of a rotor speed measurement. Further, the efficiency is based on a determination of stator winding resistance, an input voltage, and an input current. The determination of the stator winding resistance occurs while the electric motor under load is online.

  20. Previous Open Rotor Research in the US

    NASA Technical Reports Server (NTRS)

    VanZante, Dale

    2011-01-01

    Previous Open Rotor noise experience in the United States, current Open Rotor noise research in the United States and current NASA prediction methods activities were presented at a European Union (EU) X-Noise seminar. The invited attendees from EU industries, research establishments and universities discussed prospects for reducing Open Rotor noise and reviewed all technology programs, past and present, dedicated to Open Rotor engine concepts. This workshop was particularly timely because the Committee on Aviation Environmental Protection (CAEP) plans to involve Independent Experts in late 2011 in assessing the noise of future low-carbon technologies including the open rotor.

  1. Advanced Rotor Blade Materials Evaluation

    DTIC Science & Technology

    2014-07-23

    helicopter rotor blade erosion resistant treatments that had been supplied in response to a US Navy BAA Program. The Navy Program was meant to improve the...earlier ONR BAA Program had been concluded and while this specific program was active. This program was one of the drivers behind the need to

  2. Agricultural Electricity. Electric Motors. Student Manual.

    ERIC Educational Resources Information Center

    Benson, Robert T.

    Addressed to the student, this manual, which includes supplementary diagrams, discusses the following topics and principles: Electromagnetic fields, electromagnets, parts of an electric motor, determining speed of an electric motor, types of electric motors in common use (split-phase, capacitor, repulsion-induction, three-phase), the electric…

  3. Ullmann coupling mediated assembly of an electrically driven altitudinal molecular rotor.

    PubMed

    Murphy, Colin J; Smith, Zachary C; Pronschinski, Alex; Lewis, Emily A; Liriano, Melissa L; Wong, Chloe; Ivimey, Christopher J; Duffy, Mitchell; Musial, Wojciech; Therrien, Andrew J; Thomas, Samuel W; Sykes, E Charles H

    2015-12-21

    Surface-bound molecular rotation can occur with the rotational axis either perpendicular (azimuthal) or parallel (altitudinal) to the surface. The majority of molecular rotor studies involve azimuthal rotors, whereas very few altitudinal rotors have been reported. In this work, altitudinal rotors are formed by means of coupling aryl halides through a surface-mediated Ullmann coupling reaction, producing a reaction state-dependent altitudinal molecular rotor/stator. All steps in the reaction on a Cu(111) surface are visualized by low-temperature scanning tunneling microscopy. The intermediate stage of the coupling reaction is a metal-organic complex consisting of two aryl groups attached to a single copper atom with the aryl rings angled away from the surface. This conformation leads to nearly unhindered rotational motion of ethyl groups at the para positions of the aryl rings. Rotational events of the ethyl group are both induced and quantified by electron tunneling current versus time measurements and are only observed for the intermediate structure of the Ullmann coupling reaction, not the starting material or finished product in which the ethyl groups are static. We perform an extensive set of inelastic electron tunneling driven rotation experiments that reveal that torsional motion around the ethyl group is stimulated by tunneling electrons in a one-electron process with an excitation energy threshold of 45 meV. This chemically tunable system offers an ideal platform for examining many fundamental aspects of the dynamics of chemically tunable molecular rotor and motors.

  4. The effect of blade pitch in the rotor hydrodynamics of a cross-flow turbine

    NASA Astrophysics Data System (ADS)

    Somoano, Miguel; Huera-Huarte, Francisco

    2016-11-01

    In this work we will show how the hydrodynamics of the rotor of a straight-bladed Cross-Flow Turbine (CFT) are affected by the Tip Speed Ratio (TSR), and the blade pitch angle imposed to the rotor. The CFT model used in experiments consists of a three-bladed (NACA-0015) vertical axis turbine with a chord (c) to rotor diameter (D) ratio of 0.16. Planar Digital Particle Image Velocimetry (DPIV) was used, with the laser sheet aiming at the mid-span of the blades, illuminating the inner part of the rotor and the near wake of the turbine. Tests were made by forcing the rotation of the turbine with a DC motor, which provided precise control of the TSR, while being towed in a still-water tank at a constant Reynolds number of 61000. A range of TSRs from 0.7 to 2.3 were covered for different blade pitches, ranging from 8° toe-in to 16° toe-out. The interaction between the blades in the rotor will be discussed by examining dimensionless phase-averaged vorticity fields in the inner part of the rotor and mean velocity fields in the near wake of the turbine. Supported by the Spanish Ministry of Economy and Competitiveness, Grant BES-2013-065366 and project DPI2015-71645-P.

  5. Advances in tilt rotor noise prediction

    NASA Technical Reports Server (NTRS)

    George, A. R.; Coffen, C. D.; Ringler, T. D.

    1992-01-01

    The two most serious tilt rotor external noise problems, hover noise and blade-vortex interaction noise, are studied. The results of flow visualization and inflow velocity measurements document a complex, recirculating highly unsteady and turbulent flow due to the rotor-wing-body interactions characteristic of tilt rotors. The wing under the rotor is found to obstruct the inflow, causing a deficit in the inflow velocities over the inboard region of the rotor. Discrete frequency harmonic thickness and loading noise mechanisms in hover are examined by first modeling tilt rotor hover aerodynamics and then applying various noise prediction methods using the WOPWOP code. The analysis indicates that the partial ground plane created by the wing below the rotor results in a primary sound source for hover.

  6. Fuselage upwash effects on RSRA rotor systems

    NASA Technical Reports Server (NTRS)

    Cowan, J.; Dadone, L.

    1985-01-01

    The effects of RSRA fuselage configurations on rotor performance and loads have been quantified analytically by means of currently available potential flow and rotor analysis. Four configurations of the Rotor Systems Research Aircraft (RSRA) were considered in this study. They were: (1) fuselage alone (conventional helicopter); (2) fuselage with auxiliary propulsion; (3) fuselage with wings (auxiliary lift); and (4) fuselage with both auxiliary lift propulsion. The rotor system investigated was identical to a CH-47D front rotor except that it had four instead of three blades. Two scaled-down versions of the same rotor were also analyzed to determine the effect of rotor scale on the fuselage upwash effects. The flight conditions considered for the upwash study are discussed. The potential flow models for the RSRA configuration, with and without the wings and the auxiliary propulsion system, are presented. The results of fuselage/wing/propulsion system upwash on performance and loads are also presented.

  7. Power-Conserving Stepping-Motor Drive Circuits

    NASA Technical Reports Server (NTRS)

    Nola, Frank J.; Howard, David E.

    1994-01-01

    Two improved drive circuits for sinusoidally commutated stepping motor include feedback loops reducing unnecessary consumption of power by reducing drive-current amplitude, I, when motor operates under light load. Basic design strategy attempts to supply only little more current than minimum needed to overcome friction in lightly loaded condition. In this sinusoidally commutated two-phase stepping motor, magnetic field generated by drive currents in phase-A and phase-B stator windings urges rotor toward commanded angle x.

  8. Levitation Performance of Two Opposed Permanent Magnet Pole-Pair Separated Conical Bearingless Motors

    NASA Technical Reports Server (NTRS)

    Kascak, Peter; Jansen, Ralph; Dever, Timothy; Nagorny, Aleksandr; Loparo, Kenneth

    2013-01-01

    In standard motor applications, rotor suspension with traditional mechanical bearings represents the most economical solution. However, in certain high performance applications, rotor suspension without contacting bearings is either required or highly beneficial. Examples include applications requiring very high speed or extreme environment operation, or with limited access for maintenance. This paper expands upon a novel bearingless motor concept, in which two motors with opposing conical air-gaps are used to achieve full five-axis levitation and rotation of the rotor. Force in this motor is created by deliberately leaving the motor s pole-pairs unconnected, which allows the creation of different d-axis flux in each pole pair. This flux imbalance is used to create lateral force. This approach is different than previous bearingless motor designs, which require separate windings for levitation and rotation. This paper examines the predicted and achieved suspension performance of a fully levitated prototype bearingless system.

  9. Investigation of rotor blade element airloads for a teetering rotor in the blade stall regime

    NASA Technical Reports Server (NTRS)

    Dadone, L. U.; Fukushima, T.

    1974-01-01

    A model of a teetering rotor was tested in a low speed wind tunnel. Blade element airloads measured on an articulated model rotor were compared with the teetering rotor and showed that the teetering rotor is subjected to less extensive flow separation. Retreating blade stall was studied. Results show that stall, under the influence of unsteady aerodynamic effects, consists of four separate stall events, each associated with a vortex shed from the leading edge and sweeping over the upper surface of the rotor blade. Current rotor performance prediction methodology was evaluated through computer simulation.

  10. Pre-design study for a modern four-bladed rotor for the Rotor System Research Aircraft (RSRA). [integrating the YAH-64 main rotor

    NASA Technical Reports Server (NTRS)

    Hughes, C. W.; Logan, A. H.

    1981-01-01

    Various candidate rotor systems were compared in an effort to select a modern four-bladed rotor for the RSRA. The YAH-64 rotor system was chosen as the candidate rotor system for further development for the RSRA. The process used to select the rotor system, studies conducted to mate the rotor with the RSRA and provide parametric variability, and the development plan which would be used to implement these studies are presented. Drawings are included.

  11. Superconducting AC motor for centrifugal liquid helium pump

    SciTech Connect

    Rivetti, A.; Goria, R.; Martini, G.

    1982-01-01

    The behavior of flowmeters in liquid and supercritical helium is studied. A description is given of the motor and experimental apparatus. The initial results (torque vs. efficiency and power vs. slip) are chartered. The results obtained with an external rotating shield (torque vs. efficiency and power vs. slip) are also charted. One rotor provided a higher power particularly at the highest frequencies, provided that the critical point is not exceeded. Another rotor gives a better efficiency, particularly at the lowest frequencies. Recommendations for adopting a rotor design are given.

  12. Miniature high speed compressor having embedded permanent magnet motor

    NASA Technical Reports Server (NTRS)

    Zhou, Lei (Inventor); Zheng, Liping (Inventor); Chow, Louis (Inventor); Kapat, Jayanta S. (Inventor); Wu, Thomas X. (Inventor); Kota, Krishna M. (Inventor); Li, Xiaoyi (Inventor); Acharya, Dipjyoti (Inventor)

    2011-01-01

    A high speed centrifugal compressor for compressing fluids includes a permanent magnet synchronous motor (PMSM) having a hollow shaft, the being supported on its ends by ball bearing supports. A permanent magnet core is embedded inside the shaft. A stator with a winding is located radially outward of the shaft. The PMSM includes a rotor including at least one impeller secured to the shaft or integrated with the shaft as a single piece. The rotor is a high rigidity rotor providing a bending mode speed of at least 100,000 RPM which advantageously permits implementation of relatively low-cost ball bearing supports.

  13. Magnetically suspended centrifugal blood pump with an axially levitated motor.

    PubMed

    Masuzawa, Toru; Ezoe, Shiroh; Kato, Tsuyoshi; Okada, Yohji

    2003-07-01

    The longevity of a rotary blood pump is mainly determined by the durability of its wearing mechanical parts such as bearings and seals. Magnetic suspension techniques can be used to eliminate these mechanical parts altogether. This article describes a magnetically suspended centrifugal blood pump using an axially levitated motor. The motor comprises an upper stator, a bottom stator, and a levitated rotor-impeller between the stators. The upper stator has permanent magnets to generate an attractive axial bias force on the rotor and electric magnets to control the inclination of the rotor. The bottom stator has electric magnets to generate attractive forces and rotating torque to control the axial displacement and rotation of the rotor. The radial displacement of the rotor is restricted by passive stability. A shrouded impeller is integrated within the rotor. The performance of the magnetic suspension and pump were evaluated in a closed mock loop circuit filled with water. The maximum amplitude of the rotor displacement in the axial direction was only 0.06 mm. The maximum possible rotational speed during levitation was 1,600 rpm. The maximum pressure head and flow rate were 120 mm Hg and 7 L/min, respectively. The pump shows promise as a ventricular assist device.

  14. PZT Thin Film Piezoelectric Traveling Wave Motor

    NASA Technical Reports Server (NTRS)

    Shen, Dexin; Zhang, Baoan; Yang, Genqing; Jiao, Jiwei; Lu, Jianguo; Wang, Weiyuan

    1995-01-01

    With the development of micro-electro-mechanical systems (MEMS), its various applications are attracting more and more attention. Among MEMS, micro motors, electrostatic and electromagnetic, are the typical and important ones. As an alternative approach, the piezoelectric traveling wave micro motor, based on thin film material and integrated circuit technologies, circumvents many of the drawbacks of the above mentioned two types of motors and displays distinct advantages. In this paper we report on a lead-zirconate-titanate (PZT) piezoelectric thin film traveling wave motor. The PZT film with a thickness of 150 micrometers and a diameter of 8 mm was first deposited onto a metal substrate as the stator material. Then, eight sections were patterned to form the stator electrodes. The rotor had an 8 kHz frequency power supply. The rotation speed of the motor is 100 rpm. The relationship of the friction between the stator and the rotor and the structure of the rotor on rotation were also studied.

  15. A Survey of Theoretical and Experimental Coaxial Rotor Aerodynamic Research

    NASA Technical Reports Server (NTRS)

    Coleman, Colin P.

    1997-01-01

    The recent appearance of the Kamov Ka-50 helicopter and the application of coaxial rotors to unmanned aerial vehicles have renewed international interest in the coaxial rotor configuration. This report addresses the aerodynamic issues peculiar to coaxial rotors by surveying American, Russian, Japanese, British, and German research. (Herein, 'coaxial rotors' refers to helicopter, not propeller, rotors. The intermeshing rotor system was not investigated.) Issues addressed are separation distance, load sharing between rotors, wake structure, solidity effects, swirl recovery, and the effects of having no tail rotor. A general summary of the coaxial rotor configuration explores the configuration's advantages and applications.

  16. Extended core for motor/generator

    DOEpatents

    Shoykhet, Boris A.

    2005-05-10

    An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.

  17. Extended core for motor/generator

    DOEpatents

    Shoykhet, Boris A.

    2006-08-22

    An extended stator core in a motor/generator can be utilized to mitigate losses in end regions of the core and a frame of the motor/generator. To mitigate the losses, the stator core can be extended to a length substantially equivalent to or greater than a length of a magnetically active portion in the rotor. Alternatively, a conventional length stator core can be utilized with a shortened magnetically active portion to mitigate losses in the motor/generator. To mitigate the losses in the core caused by stator winding, the core can be extended to a length substantially equivalent or greater than a length of stator winding.

  18. Controller for computer control of brushless dc motors. [automobile engines

    NASA Technical Reports Server (NTRS)

    Hieda, L. S. (Inventor)

    1981-01-01

    A motor speed and torque controller for brushless d.c. motors provides an unusually smooth torque control arrangement. The controller provides a means for controlling a current waveform in each winding of a brushless dc motor by synchronization of an excitation pulse train from a programmable oscillator. Sensing of torque for synchronization is provided by a light beam chopper mounted on the motor rotor shaft. Speed and duty cycle are independently controlled by controlling the frequency and pulse width output of the programmable oscillator. A means is also provided so that current transitions from one motor winding to another is effected without abrupt changes in output torque.

  19. Rotor blade vortex interaction noise

    NASA Astrophysics Data System (ADS)

    Yu, Yung H.

    2000-02-01

    Blade-vortex interaction noise-generated by helicopter main rotor blades is one of the most severe noise problems and is very important both in military applications and community acceptance of rotorcraft. Research over the decades has substantially improved physical understanding of noise-generating mechanisms, and various design concepts have been investigated to control noise radiation using advanced blade planform shapes and active blade control techniques. The important parameters to control rotor blade-vortex interaction noise and vibration have been identified: blade tip vortex structures and its trajectory, blade aeroelastic deformation, and airloads. Several blade tip design concepts have been investigated for diffusing tip vortices and also for reducing noise. However, these tip shapes have not been able to substantially reduce blade-vortex interaction noise without degradation of rotor performance. Meanwhile, blade root control techniques, such as higher-harmonic pitch control (HHC) and individual blade control (IBC) concepts, have been extensively investigated for noise and vibration reduction. The HHC technique has proved the substantial blade-vortex interaction noise reduction, up to 6 dB, while vibration and low-frequency noise have been increased. Tests with IBC techniques have shown the simultaneous reduction of rotor noise and vibratory loads with 2/rev pitch control inputs. Recently, active blade control concepts with smart structures have been investigated with the emphasis on active blade twist and trailing edge flap. Smart structures technologies are very promising, but further advancements are needed to meet all the requirements of rotorcraft applications in frequency, force, and displacement.

  20. Rotor blades for turbine engines

    DOEpatents

    Piersall, Matthew R; Potter, Brian D

    2013-02-12

    A tip shroud that includes a plurality of damping fins, each damping fin including a substantially non-radially-aligned surface that is configured to make contact with a tip shroud of a neighboring rotor blade. At least one damping fin may include a leading edge damping fin and at least one damping fin may include a trailing edge damping fin. The leading edge damping fin may be configured to correspond to the trailing edge damping fin.

  1. System and method to determine electric motor efficiency nonintrusively

    DOEpatents

    Lu, Bin; Habetler, Thomas G.; Harley, Ronald G.

    2011-08-30

    A system and method for nonintrusively determining electric motor efficiency includes a processor programed to, while the motor is in operation, determine a plurality of stator input currents, electrical input data, a rotor speed, a value of stator resistance, and an efficiency of the motor based on the determined rotor speed, the value of stator resistance, the plurality of stator input currents, and the electrical input data. The determination of the rotor speed is based on one of the input power and the plurality of stator input currents. The determination of the value of the stator resistance is based on at least one of a horsepower rating and a combination of the plurality of stator input currents and the electrical input data. The electrical input data includes at least one of an input power and a plurality of stator input voltages.

  2. Magnetic Circuit Model of PM Motor-Generator to Predict Radial Forces

    NASA Technical Reports Server (NTRS)

    McLallin, Kerry (Technical Monitor); Kascak, Peter E.; Dever, Timothy P.; Jansen, Ralph H.

    2004-01-01

    A magnetic circuit model is developed for a PM motor for flywheel applications. A sample motor is designed and modeled. Motor configuration and selection of materials is discussed, and the choice of winding configuration is described. A magnetic circuit model is described, which includes the stator back iron, rotor yoke, permanent magnets, air gaps and the stator teeth. Iterative solution of this model yields flux linkages, back EMF, torque, power, and radial force at the rotor caused by eccentricity. Calculated radial forces are then used to determine motor negative stiffness.

  3. A study of rotor broadband noise mechanisms and helicopter tail rotor noise

    NASA Technical Reports Server (NTRS)

    Chou, Shau-Tak Rudy

    1990-01-01

    The rotor broadband noise mechanisms considered are the following: (1) lift fluctuation due to turbulence ingestion; (2) boundary layer/trailing edge interaction; (3) tip vortex formation; and (4) turbulent vortex shedding from blunt trailing edge. Predictions show good agreement with available experimental data. The study shows that inflow turbulence is the most important broadband noise source for typical helicopters' main rotors at low- and mid-frequencies. Due to the size difference, isolated helicopter tail rotor broadband noise is not important compared to the much louder main rotor broadband noise. However, the inflow turbulence noise from a tail rotor can be very significant because it is operating in a highly turbulent environment, ingesting wakes from upstream components of the helicopter. The study indicates that the main rotor turbulent wake is the most important source of tail rotor broadband noise. The harmonic noise due to ingestion of main rotor tip vortices is studied.

  4. An unsteady rotor/fuselage interaction method

    NASA Technical Reports Server (NTRS)

    Egolf, T. Alan; Lorber, Peter F.

    1987-01-01

    An analytical method has been developed to treat unsteady helicopter rotor, wake, and fuselage interaction aerodynamics. An existing lifting line/prescribed wake rotor analysis and a source panel fuselage analysis were modified to predict vibratory fuselage airloads. The analyses were coupled through the induced flow velocities of the rotor and wake on the fuselage and the fuselage on the rotor. A prescribed displacement technique was used to distort the rotor wake about the fuselage. Sensitivity studies were performed to determine the influence of wake and body geometry on the computed airloads. Predicted and measured mean and unsteady pressures on a cylindrical body in the wake of a two-bladed rotor were compared. Initial results show good qualitative agreement.

  5. Parametric tip effects for conformable rotor applications

    NASA Technical Reports Server (NTRS)

    Mantay, W. R.; Yeager, W. T., Jr.

    1983-01-01

    A research study was initiated to systematically determine the impact of selected blade tip geometric parameters on aeroelasticity conformable rotor performance and loads characteristics. The model articulated rotors included baseline and torsionally soft blades with interchangeable tips. Seven blade tip designs were evaluated on the baseline rotor and three tip designs were tested on the torsionally soft blades. The designs incorporated a systematic variation in three geometric parameters: sweep, taper, and anhedral. The rotors were evaluated in the NASA Langley Transonic Dynamics Tunnel at several advance ratios, lift and propulsive force values, and tip Mach numbers. Based on the test results, tip parameter variations generated significant rotor performance and loads difference for both baseline and torsionally soft blades. Azimuthal variation of elastic twist generated by the tip parameters strongly correlated with rotor performance and loads, but the magnitude of advancing blade elastic twist did not correlate.

  6. Submersible canned motor transfer pump

    DOEpatents

    Guardiani, Richard F.; Pollick, Richard D.; Nyilas, Charles P.; Denmeade, Timothy J.

    1997-01-01

    A transfer pump used in a waste tank for transferring high-level radioactive liquid waste from a waste tank and having a column assembly, a canned electric motor means, and an impeller assembly with an upper impeller and a lower impeller connected to a shaft of a rotor assembly. The column assembly locates a motor housing with the electric motor means adjacent to the impeller assembly which creates an hydraulic head, and which forces the liquid waste, into the motor housing to cool the electric motor means and to cool and/or lubricate the radial and thrust bearing assemblies. Hard-on-hard bearing surfaces of the bearing assemblies and a ring assembly between the upper impeller and electric motor means grind large particles in the liquid waste flow. Slots in the static bearing member of the radial bearing assemblies further grind down the solid waste particles so that only particles smaller than the clearances in the system can pass therethrough, thereby resisting damage to and the interruption of the operation of the transfer pump. The column assembly is modular so that sections can be easily assembled, disassembled and/or removed. A second embodiment employs a stator jacket which provides an alternate means for cooling the electric motor means and lubricating and/or cooling the bearing assemblies, and a third embodiment employs a variable level suction device which allows liquid waste to be drawn into the transfer pump from varying and discrete levels in the waste tank.

  7. Characterizing the effects of friction liner materials on the performance of piezoelectric motors using finite element analysis

    SciTech Connect

    Gute, G.D.; Halter, S.L.

    1995-10-01

    A finite element model of a Panasonic USM-40D piezoelectric motor`s rotor was coupled with a finite element model of the motor`s friction liner/rotor so that the frictional interface could be further studied. Results from the model were used to study the affects of various friction liner material properties on motor stall torque. Statistical methods were used to determine the significant friction liner material properties and their interactions. An equation for predicting the stall torque as a function of the significant variables and their interactions was established.

  8. High-performance permanent magnet brushless motors with balanced concentrated windings and similar slot and pole numbers

    NASA Astrophysics Data System (ADS)

    Štumberger, Bojan; Štumberger, Gorazd; Hadžiselimović, Miralem; Hamler, Anton; Trlep, Mladen; Goričan, Viktor; Jesenik, Marko

    2006-09-01

    The paper presents a comparison between the performances of exterior-rotor permanent magnet brushless motors with distributed windings and the performances of exterior-rotor permanent magnet brushless motors with concentrated windings. Finite element method analysis is employed to determine the performance of each motor. It is shown that motors with concentrated windings and similar slot and pole numbers exhibit similar or better performances than motors with distributed windings for brushless AC (BLAC) operation mode and brushless DC (BLDC) operation mode as well.

  9. Rotor fatigue monitoring data acquisition system

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.

    1993-01-01

    The 40 by 80 Foot Wind Tunnel of the National Full Scale Aerodynamics Complex (NFAC) had a requirement to monitor rotor fatigue during a test. This test subjected various rotor components to stress levels higher than their structural fatigue limits. A data acquisition system was developed to monitor the cumulative fatigue damage of rotor components using National Instruments hardware and LabVIEW software. A full description of the data acquisition system including its configuration and salient features, is presented in this paper.

  10. Eigenvalues and stability problems of rotors

    NASA Technical Reports Server (NTRS)

    Walczyk, Z.

    1985-01-01

    The essential theoretical results of the application of a developed transfer matrix method to the free transverse vibration of a rotor are shown. Gyroscopic and shear effects, rotary inertia, and external and internal damping as well as the influence of sleeve bearings and rotor supports are taken into consideration. The eigenvalues of the motion equations of the rotor are searched by using a modified determinant method.

  11. Inertial dynamics of a general purpose rotor

    NASA Technical Reports Server (NTRS)

    Duval, R. W.

    1979-01-01

    The inertial dynamics of a fully articulated stiff rotor blade are derived with emphasis on equations that facilitate an organized programming approach for simulation applications. The model for the derivation includes hinge offset and six degrees of freedom for the rotor shaft. Results are compared with the flapping and lead-lag equations currently used in the Rotor Systems Research Aircraft simulation model and differences are analyzed.

  12. Flywheel Rotor Safe-Life Technology

    NASA Technical Reports Server (NTRS)

    Ratner, J. K. H.; Chang, J. B.; Christopher, D. A.; McLallin, Kerry L. (Technical Monitor)

    2002-01-01

    Since the 1960s, research has been conducted into the use of flywheels as energy storage systems. The-proposed applications include energy storage for hybrid and electric automobiles, attitude control and energy storage for satellites, and uninterruptible power supplies for hospitals and computer centers. For many years, however, the use of flywheels for space applications was restricted by the total weight of a system employing a metal rotor. With recent technological advances in the manufacturing of composite materials, however, lightweight composite rotors have begun to be proposed for such applications. Flywheels with composite rotors provide much higher power and energy storage capabilities than conventional chemical batteries. However, the failure of a high speed flywheel rotor could be a catastrophic event. For this reason, flywheel rotors are classified by the NASA Fracture Control Requirements Standard as fracture critical parts. Currently, there is no industry standard to certify a composite rotor for safe and reliable operation forth( required lifetime of the flywheel. Technical problems hindering the development of this standard include composite manufacturing inconsistencies, insufficient nondestructive evaluation (NDE) techniques for detecting defects and/or impact damage, lack of standard material test methods for characterizing composite rotor design allowables, and no unified proof (over-spin) test for flight rotors. As part of a flywheel rotor safe-life certification pro-ram funded b the government, a review of the state of the art in composite rotors is in progress. The goal of the review is to provide a clear picture of composite flywheel rotor technologies. The literature review has concentrated on the following topics concerning composites and composite rotors: durability (fatigue) and damage tolerance (safe-life) analysis/test methods, in-service NDE and health monitoring techniques, spin test methods/ procedures, and containment options

  13. Non-Synchronous Whirling Due to Fluid-Dynamic Forces in Axial Turbo-Machinery Rotors

    NASA Technical Reports Server (NTRS)

    Shen, S. F.; Mengle, V. G.

    1980-01-01

    The role of fluid forces acting on the blades of an axial turborotor with regards to whirling was analyzed. The dynamic equations were formulated for the coning mode of an overhung rotor. The exciting forces due to the motion were defined through a set of rotor stability derivatives, and analytical expressions of the aerodynamic contributions were found for the case of small mean stream deflection, high solidity and equivalent flat plate cascade. For a typical case, only backward whirl was indicated when the phase shifting of the rotor wake effect was ignored. A parametric study of the dynamic stability boundary reveals that a reduction in blade stagger angle, mass flow rate, fluid density and an increase in stiffness and external damping are all inductive for improved stability.

  14. Synchronization analysis and control of three eccentric rotors in a vibrating system using adaptive sliding mode control algorithm

    NASA Astrophysics Data System (ADS)

    Kong, Xiangxi; Zhang, Xueliang; Chen, Xiaozhe; Wen, Bangchun; Wang, Bo

    2016-05-01

    In this paper, self- and controlled synchronizations of three eccentric rotors (ERs) in line driven by induction motors rotating in the same direction in a vibrating system are investigated. The vibrating system is a typical underactuated mechanical-electromagnetic coupling system. The analysis and control of the vibrating system convert to the synchronization motion problem of three ERs. Firstly, the self-synchronization motion of three ERs is analyzed according to self-synchronization theory. The criterions of synchronization and stability of self-synchronous state are obtained by using a modified average perturbation method. The significant synchronization motion of three ERs with zero phase differences cannot be implemented according to self-synchronization theory through analysis and simulations. To implement the synchronization motion of three ERs with zero phase differences, an adaptive sliding mode control (ASMC) algorithm based on a modified master-slave control strategy is employed to design the controllers. The stability of the controllers is verified by using Lyapunov theorem. The performances of the controlled synchronization system are presented by simulations to demonstrate the effectiveness of controllers. Finally, the effects of reference speed and non-zero phase differences on the controlled system are discussed to show the strong robustness of the proposed controllers. Additionally, the dynamic responses of the vibrating system in different synchronous states are analyzed.

  15. Design of helicopter rotors to noise constraints

    NASA Technical Reports Server (NTRS)

    Schaeffer, E. G.; Sternfeld, H., Jr.

    1978-01-01

    Results of the initial phase of a research project to study the design constraints on helicopter noise are presented. These include the calculation of nonimpulsive rotor harmonic and broadband hover noise spectra, over a wide range of rotor design variables and the sensitivity of perceived noise level (PNL) to changes in rotor design parameters. The prediction methodology used correlated well with measured whirl tower data. Application of the predictions to variations in rotor design showed tip speed and thrust as having the most effect on changing PNL.

  16. Rotor/wing aerodynamic interactions in hover

    NASA Technical Reports Server (NTRS)

    Felker, F. F.; Light, J. S.

    1986-01-01

    An experimental and theoretical investigation of rotor/wing aerodynamic interactions in hover is described. The experimental investigation consisted of both a large-scale and small-scale test. A 0.658-scale, V-22 rotor and wing was used in the large-scale test. Wind download, wing surface pressure, rotor performance, and rotor downwash data from the large-scale test are presented. A small-scale experiment was conducted to determine how changes in the rotor/wing geometry affected the aerodynamic interactions. These geometry variations included the distance between the rotor and wing, wing incidence angle, and configurations both with the rotor axis at the tip of the wing (tilt rotor configuration) and with the rotor axis at the center of the wing (compound helicopter configuration). A wing with boundary-layer control was also tested to evaluate the effect of leading and trailing edge upper surface blowing on the wing download. A computationally efficient, semi-empirical theory was developed to predict the download on the wing. Finally, correlations between the theoretical predictions and test data are presented.

  17. Prediction of helicopter rotor rotational noise

    NASA Astrophysics Data System (ADS)

    Xu, Guohua; Gao, Zheng

    1991-06-01

    Based on Farassat (1981) formulation 1A for subsonic time domain, a method is developed for predicting the rotor rotational noise, which is valid for arbitrary observer positions and all linear flight conditions. Without considering the elasticity of the blade, the retarded time equation and all of the integrands in the formulation 1A are derived and expressed as the proper form for numerical calculation. As examples, the noise calculation of the helicopter Z-8 rotor and 1/4 scale UH-1 rotor in hover are carried out. Discussions are presented on the influence of rotor parameters, such as the tip Mach number, the disk loading, and the blade airfoil.

  18. Rotor thermal stress monitoring in steam turbines

    NASA Astrophysics Data System (ADS)

    Antonín, Bouberle; Jan, Jakl; Jindřich, Liška

    2015-11-01

    One of the issues of steam turbines diagnostics is monitoring of rotor thermal stress that arises from nonuniform temperature field. The effort of steam turbine operator is to operate steam turbine in such conditions, that rotor thermal stress doesn't exceed the specified limits. If rotor thermal stress limits are exceeded for a long time during machine operation, the rotor fatigue life is shortened and this may lead to unexpected machine failure. Thermal stress plays important role during turbine cold startup, when occur the most significant differences of temperatures through rotor cross section. The temperature field can't be measured directly in the entire rotor cross section and standardly the temperature is measured by thermocouple mounted in stator part. From this reason method for numerical solution of partial differential equation of heat propagation through rotor cross section must be combined with method for calculation of temperature on rotor surface. In the first part of this article, the application of finite volume method for calculation of rotor thermal stress is described. The second part of article deals with optimal trend generation of thermal flux, that could be used for optimal machine loading.

  19. Dynamic Balancing Of Turbomachinery Shafts And Rotors

    NASA Technical Reports Server (NTRS)

    Verhoff, Vincent G.

    1993-01-01

    Method for dynamic balancing of turbomachinery shafts and rotors developed with view toward reducing time spent in balancing process. Improved method based on existing dynamic-balancing techniques and equipment, incorporating use of balancing arbor, which is mandrel duplicating mounting geometry and dynamic-balance properties of shaft balanced. Once shaft balanced, not necessary to disassemble machinery and/or shaft completely and rebalance shaft when replacing rotor on shaft. Instead, one balances replacement rotor on balancing arbor, then installs balanced rotor on shaft.

  20. Rotor Flapping Response to Active Control

    NASA Technical Reports Server (NTRS)

    Nguyen, Khanh; Johnson, Wayne

    2004-01-01

    Rotor active control using higher harmonic blade pitch has been proposed as a means to reduce both rotor radiated noise and airframe vibration and to enhance rotor performance. The higher harmonic input, however, can affect rotor thrust and cyclic flapping - the basic trim characteristics of the rotor. Some of the trim changes can negate the active control benefits. For example, wind tunnel test results of a full scale BO-105 rotor with individual-blade control indicate some rotor performance improvements, accompanied with changes in rotor trim, using two-per-rev blade pitch input. The observed performance benefits could therefore be a simple manifestation of the trim change rather than an efficient redistribution of the rotor airloads. More recently, the flight test of the BO-105 helicopter equip,ped with individual-blade-control actuators also reported trim changes whenever the two-per-rev blade pitch for noise reduction was activated. The pilot had to adjust the trim control to maintain the aircraft under a constant flight path. These two cases highlight the, importance of trim considerations in the application of active control to rotorcraft.

  1. High Speed Rotor Head Mounted Instrumentation System

    NASA Technical Reports Server (NTRS)

    Hee, Leonard; Reynolds, R. S. (Technical Monitor)

    1997-01-01

    NASA Ames Research Center has been investigating the air flow of a rotor blade on a UH-60 Blackhawk helicopter in-flight. This paper will address the hardware problems and solutions used to design and fabricate an instrumentation system on top of a UH-60 main rotor head. The instrumentation system consisted of 10 data systems operating in parallel and collected data from 370 sensors that are mounted in four rotor blades and on the rotating rotor head. The data was recorded on board the aircraft and simultaneously down linked to the ground station at 7.5 MHz.

  2. Identification and Reconfigurable Control of Impaired Multi-Rotor Drones

    NASA Technical Reports Server (NTRS)

    Stepanyan, Vahram; Krishnakumar, Kalmanje; Bencomo, Alfredo

    2016-01-01

    The paper presents an algorithm for control and safe landing of impaired multi-rotor drones when one or more motors fail simultaneously or in any sequence. It includes three main components: an identification block, a reconfigurable control block, and a decisions making block. The identification block monitors each motor load characteristics and the current drawn, based on which the failures are detected. The control block generates the required total thrust and three axis torques for the altitude, horizontal position and/or orientation control of the drone based on the time scale separation and nonlinear dynamic inversion. The horizontal displacement is controlled by modulating the roll and pitch angles. The decision making algorithm maps the total thrust and three torques into the individual motor thrusts based on the information provided by the identification block. The drone continues the mission execution as long as the number of functioning motors provide controllability of it. Otherwise, the controller is switched to the safe mode, which gives up the yaw control, commands a safe landing spot and descent rate while maintaining the horizontal attitude.

  3. Cogging Torque Characteristics of a Magnetic-Geared Motor

    NASA Astrophysics Data System (ADS)

    Niguchi, Noboru; Hirata, Katsuhiro

    This paper describes the cogging torque characteristics of a magnetic-geared motor with permanent magnets only on the high-speed rotor. The operational principle, which is different from that of the magnetic-geared motor with permanent magnets on the high-speed rotor and stator, is described. The torque characteristics, especially the order of the cogging torque, are mathematically formulated and verified by conducting 3-D finite element analysis and carrying out measurements on a prototype. Furthermore, a novel cogging torque reduction method is proposed and verified as well.

  4. Method for manufacturing a rotor having superconducting coils

    DOEpatents

    Driscoll, David I.; Shoykhet, Boris A.

    2001-01-01

    A method and apparatus for manufacturing a rotor for use with a rotating machine is provided that employs a superconducting coil on the rotor. An adhesive is applied to an outer surface of the rotor body, which may include a groove disposed within an outer surface of the rotor body. A superconducting coil is then mounted onto the rotor body such that the adhesive bonds the superconducting coil to the rotor body.

  5. Dynamic Rotor Deformation and Vibration Monitoring Using a Non-Incremental Laser Doppler Distance Sensor

    SciTech Connect

    Pfister, Thorsten; Guenther, Philipp; Dreier, Florian; Czarske, Juergen

    2010-05-28

    Monitoring rotor deformations and vibrations dynamically is an important task for improving the safety and the lifetime as well as the energy efficiency of motors and turbo machines. However, due to the high rotor speed encountered in particular at turbo machines, this requires concurrently a high measurement rate and high accuracy, which can not be fulfilled by most commercially available sensors. To solve this problem, we developed a non-incremental laser Doppler distance sensor (LDDS), which is able to measure simultaneously the in-plane velocity and the out-of-plane position of moving rough solid objects with micrometer precision. In addition, this sensor concurrently offers a high temporal resolution in the microsecond range, because its position uncertainty is in principle independent of the object velocity in contrast to conventional distance sensors, which is a unique feature of the LDDS. Consequently, this novel sensor enables precise and dynamic in-process deformation and vibration measurements on rotating objects, such as turbo machine rotors, even at very high speed. In order to evidence the capability of the LDDS, measurements of rotor deformations (radial expansion), vibrations and wobbling motions are presented at up to 50,000 rpm rotor speed.

  6. Dynamic Rotor Deformation and Vibration Monitoring Using a Non-Incremental Laser Doppler Distance Sensor

    NASA Astrophysics Data System (ADS)

    Pfister, Thorsten; Günther, Philipp; Dreier, Florian; Czarske, Jürgen

    2010-05-01

    Monitoring rotor deformations and vibrations dynamically is an important task for improving the safety and the lifetime as well as the energy efficiency of motors and turbo machines. However, due to the high rotor speed encountered in particular at turbo machines, this requires concurrently a high measurement rate and high accuracy, which can not be fulfilled by most commercially available sensors. To solve this problem, we developed a non-incremental laser Doppler distance sensor (LDDS), which is able to measure simultaneously the in-plane velocity and the out-of-plane position of moving rough solid objects with micrometer precision. In addition, this sensor concurrently offers a high temporal resolution in the microsecond range, because its position uncertainty is in principle independent of the object velocity in contrast to conventional distance sensors, which is a unique feature of the LDDS. Consequently, this novel sensor enables precise and dynamic in-process deformation and vibration measurements on rotating objects, such as turbo machine rotors, even at very high speed. In order to evidence the capability of the LDDS, measurements of rotor deformations (radial expansion), vibrations and wobbling motions are presented at up to 50,000 rpm rotor speed.

  7. New Technique of High-Performance Torque Control Developed for Induction Machines

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.

    2003-01-01

    Two forms of high-performance torque control for motor drives have been described in the literature: field orientation control and direct torque control. Field orientation control has been the method of choice for previous NASA electromechanical actuator research efforts with induction motors. Direct torque control has the potential to offer some advantages over field orientation, including ease of implementation and faster response. However, the most common form of direct torque control is not suitable for the highspeed, low-stator-flux linkage induction machines designed for electromechanical actuators with the presently available sample rates of digital control systems (higher sample rates are required). In addition, this form of direct torque control is not suitable for the addition of a high-frequency carrier signal necessary for the "self-sensing" (sensorless) position estimation technique. This technique enables low- and zero-speed position sensorless operation of the machine. Sensorless operation is desirable to reduce the number of necessary feedback signals and transducers, thus improving the reliability and reducing the mass and volume of the system. This research was directed at developing an alternative form of direct torque control known as a "deadbeat," or inverse model, solution. This form uses pulse-width modulation of the voltage applied to the machine, thus reducing the necessary sample and switching frequency for the high-speed NASA motor. In addition, the structure of the deadbeat form allows the addition of the high-frequency carrier signal so that low- and zero-speed sensorless operation is possible. The new deadbeat solution is based on using the stator and rotor flux as state variables. This choice of state variables leads to a simple graphical representation of the solution as the intersection of a constant torque line with a constant stator flux circle. Previous solutions have been expressed only in complex mathematical terms without a

  8. Electrode geometry for electrostatic generators and motors

    DOEpatents

    Post, Richard F.

    2016-02-23

    An electrostatic (ES) device is described with electrodes that improve its performance metrics. Devices include ES generators and ES motors, which are comprised of one or more stators (stationary members) and one or more rotors (rotatable members). The stator and rotors are configured as a pair of concentric cylindrical structures and aligned about a common axis. The stator and rotor are comprised of an ensemble of discrete, longitudinal electrodes, which are axially oriented in an annular arrangement. The shape of the electrodes described herein enables the ES device to function at voltages significantly greater than that of the existing art, resulting in devices with greater power-handling capability and overall efficiency. Electrode shapes include, but are not limited to, rods, corrugated sheets and emulations thereof.

  9. Development and study of novel non-contact ultrasonic motor based on principle of structural asymmetry.

    PubMed

    Stepanenko, Dmitry A; Minchenya, Vladimir T

    2012-09-01

    The article presents novel design of non-contact rotary ultrasonic motor consisting of ring-shaped stator vibrating in in-plane flexural mode and rotor provided with blades. In contrast to other motors with similar design proposed motor relies on the use of standing ultrasonic waves. This simplifies design and electronic control of motor and becomes possible due to introduction of artificial asymmetry, for example by tilting one or several blades of the rotor relative to the surface normal. Operating principle of the proposed motor is based on acoustic radiation torque exerted on rotor by ultrasonic waves propagating in air or fluid gap between rotor and stator. This torque is calculated using finite element method by means of COMSOL Multiphysics software. Dynamics of rotor is studied using MathCad software and general theory of nonlinear conservative oscillators. Role of asymmetry is explained on the basis of comparative analysis of potential functions and phase trajectories for symmetric and asymmetric cases. It is shown that direction of rotation is determined by structural parameters of motor, particularly tilting direction (clockwise or counter-clockwise) of the blades. Conceptual design of motor with bidirectional rotation is described. Direction and velocity of rotation in the proposed conceptual design can be potentially controlled by changing excitation frequency of stator.

  10. Recent developments in the dynamics of advanced rotor systems

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1985-01-01

    The problems that were encountered in the dynamics of advanced rotor systems are described. The methods for analyzing these problems are discussed, as are past solutions of the problems. To begin, the basic dynamic problems of rotors are discussed: aeroelastic stability, rotor and airframe loads, and aircraft vibration. Next, advanced topics that are the subject of current research are described: vibration control, dynamic upflow, finite element analyses, and composite materials. Finally, the dynamics of various rotorcraft configurations are considered: hingeless rotors, bearingless rotors, rotors with circulation control, coupled rotor/engine dynamics, articulated rotors, and tilting proprotor aircraft.

  11. Gravitational induction

    NASA Astrophysics Data System (ADS)

    Bini, Donato; Cherubini, Christian; Chicone, Carmen; Mashhoon, Bahram

    2008-11-01

    We study the linear post-Newtonian approximation to general relativity known as gravitoelectromagnetism (GEM); in particular, we examine the similarities and differences between GEM and electrodynamics. Notwithstanding some significant differences between them, we find that a special nonstationary metric in GEM can be employed to show explicitly that it is possible to introduce gravitational induction within GEM in close analogy with Faraday's law of induction and Lenz's law in electrodynamics. Some of the physical implications of gravitational induction are briefly discussed.

  12. Comparison of Tone Mode Measurements for a Forward Swept and Baseline Rotor Fan

    NASA Technical Reports Server (NTRS)

    Heidelberg, Laurence J.

    2003-01-01

    A forward swept fan, designated the Quite High Speed Fan (QHSF), was tested in the NASA Glenn 9- by 15-foot Low Speed Wind Tunnel to investigate its noise reduction relative to a baseline fan of the same aerodynamic performance. The design objective of the QHSF was a 6 dB reduction in Effective Perceived Noise Level relative to the baseline fan at the takeoff condition. The design noise reduction was to be a result of lower levels of multiple pure tone noise due to the forward swept rotor, and lower rotor/stator interaction tone noise from a leaned stator. Although the design 6 dB reduction was observed in far-field measurements, the induct mode measurements revealed the reasons for goals. All of the noise reduction was from the blade passing tone and its harmonics and most of this was unexpectedly from rotor/strut interaction modes. The reason for large differences in rotor/strut noise sources could not be determined with certainty. The reductions in the multiple pure tone noise for the forward swept rotor were not observed. this reduction were not the ones related to the design

  13. Inductive reasoning.

    PubMed

    Hayes, Brett K; Heit, Evan; Swendsen, Haruka

    2010-03-01

    Inductive reasoning entails using existing knowledge or observations to make predictions about novel cases. We review recent findings in research on category-based induction as well as theoretical models of these results, including similarity-based models, connectionist networks, an account based on relevance theory, Bayesian models, and other mathematical models. A number of touchstone empirical phenomena that involve taxonomic similarity are described. We also examine phenomena involving more complex background knowledge about premises and conclusions of inductive arguments and the properties referenced. Earlier models are shown to give a good account of similarity-based phenomena but not knowledge-based phenomena. Recent models that aim to account for both similarity-based and knowledge-based phenomena are reviewed and evaluated. Among the most important new directions in induction research are a focus on induction with uncertain premise categories, the modeling of the relationship between inductive and deductive reasoning, and examination of the neural substrates of induction. A common theme in both the well-established and emerging lines of induction research is the need to develop well-articulated and empirically testable formal models of induction. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

  14. Multiple piece turbine rotor blade

    DOEpatents

    Jones, Russell B; Fedock, John A

    2013-05-21

    A multiple piece turbine rotor blade with a shell having an airfoil shape and secured between a spar and a platform with the spar including a tip end piece. a snap ring fits around the spar and abuts against the spar tip end piece on a top side and abuts against a shell on the bottom side so that the centrifugal loads from the shell is passed through the snap ring and into the spar and not through a tip cap dovetail slot and projection structure.

  15. Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

    SciTech Connect

    Crapo, A.D.; Lloyd, J.D. )

    1991-03-01

    This paper reports on two motors designed and built for use with high temperature superconductor (HTSC) materials. They are a homopolar DC motor that will use HTSC field windings and a brushless DC motor that will use bulk HTSC material to trap flux in steel rotor poles. The HTSC field windings of the homopolar DC motor are designed to operate at 1000 Amperes/cm{sup 2} in a 0.010 Tesla (100 Gauss) field. In order to maximize torque in the homopolar DC motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar DC motor has been tested while the authors wait for 575 Ampere turn HTSC coils.

  16. A microrotary motor powered by bacteria

    NASA Astrophysics Data System (ADS)

    Hiratsuka, Yuichi; Miyata, Makoto; Tada, Tetsuya; Uyeda, Taro Q. P.

    2006-09-01

    Biological molecular motors have a number of unique advantages over artificial motors, including efficient conversion of chemical energy into mechanical work and the potential for self-assembly into larger structures, as is seen in muscle sarcomeres and bacterial and eukaryotic flagella. The development of an appropriate interface between such biological materials and synthetic devices should enable us to realize useful hybrid micromachines. Here we describe a microrotary motor composed of a 20-μm-diameter silicon dioxide rotor driven on a silicon track by the gliding bacterium Mycoplasma mobile. This motor is fueled by glucose and inherits some of the properties normally attributed to living systems. glucose | micro actuator | motor protein | nanobiotechnology | Mycoplasma gliding

  17. High efficiency motor rewind study

    NASA Astrophysics Data System (ADS)

    Wallace, A. K.; Spee, R.

    1991-02-01

    The objective of performing this work was to evaluate a new technology used for rewinding electric motors. Motor performance evaluation was conducted at the motor test facility at Oregon State University. The test program consisted of comparing new high efficiency motor technology and standard rewind technology with the Unity-Plus system. The Unity-Plus configuration exhibited reduced efficiency over the complete load range compared to the other motors. Appropriately sized capacitors connected to the terminals of the conventional induction motor produced the same power factor improvement as the Unity-Plus system. Torque production and torque pulsation were very similar for all systems. The Unity-Plus configuration drew lower starting currents but the duration of the starting transient was increased. Motor temperature rise was about the same for all systems. Noise levels were about the same in all systems. Although determination of time to failure was not undertaken, the expected lifetime of the Unit-Plus system is probably less due to higher capacitor stress and higher insulation stress. The investigation concludes that a conventional induction motor with terminal capacitors is the most acceptable way of obtaining good efficiency and power factor and the Unity-Plus system cannot be recommended on the basis of any of the evaluation criteria used in this study.

  18. Pneumatic boot for helicopter rotor deicing

    NASA Technical Reports Server (NTRS)

    Blaha, B. J.; Evanich, P. L.

    1981-01-01

    Pneumatic deicer boots for helicopter rotor blades were tested. The tests were conducted in the 6 by 9 ft icing research tunnel on a stationary section of a UH-IH helicopter main rotor blade. The boots were effective in removing ice and in reducing aerodynamic drag due to ice.

  19. Total main rotor isolation system analysis

    NASA Technical Reports Server (NTRS)

    Sankewitsch, V.

    1981-01-01

    Requirements, preliminary design, and verification procedures for a total main rotor isolation system at n/rev are presented. The fuselage is isolated from the vibration inducing main rotor at one frequency in all degrees of freedom by four antiresonant isolation units. Effects of parametric variations on isolation system performance are evaluated.

  20. Prediction and reduction of rotor broadband noise

    NASA Technical Reports Server (NTRS)

    Hayden, R. E.; Aravamudan, K. S.

    1978-01-01

    Prediction techniques which can be or have been applied to subsonic rotors, and methods for designing helicopter rotors for reduced broadband noise generation are summarized. It is shown how detailed physical models of the noise source can be used to identify approaches to noise control.