Ac loss measurements have been performed in samples of a prototype conductor being developed for application in the central solenoid of NET. Two types of losses have been measured: hysteresis losses in the strand, and coupling losses in the strand, ...
National Technical Information Service (NTIS)
... Accession Number : ADA038393. Title : Measurements of AC Losses in Superconductors below Hc1. Descriptive Note : Final rept. Jan 74-Jun 76,. ...
DTIC Science & Technology
The theory and calculation of a.c. losses in type II superconducting materials and superconducting coils are presented. The calculated losses are compared to loss-measurements in solenoids performed by several laboratories. Methods of loss measurements are described. ...
Energy Citations Database
... report results from a contract tasking University of Cambridge as follows: The contractor will investigate: (a) Measure the AC losses of appropriate ...
In this paper a description is given of a method to measure calorimetrically ac losses in superconducting samples. The boil-off gas is stored below the liquid helium level in a measuring tube. Losses in the range of 1 mW up to 100 mW can be measured with an accuracy of 3%. ...
The measurement of ac losses in superconducting cables by calorimetric means is necessary as a verification of electronic measurements on short high-current models and because the present method of electronic measurement is not applicable to longer cables...
A calorimeter has been developed to measure the total core loss in small samples of magnetic materials which are not suited to conventional measurement techniques. The method is similar to the helium boil-off calorimeter used in some cases to measure ac l...
The objective of the program was to study the feasibility of Nb3Ge being used as an AC superconducting power transmission cable material. Specifically, the program was to measure AC losses in available samples of Nb3Ge and find under what conditions the l...
An improved electronic method for measuring ac losses in superconducting cables of lengths from 1m to 10m has been developed and is described. This method compensates for phase shifts in the measuring circuit elements and for imbalance of the difference a...
AC losses in full length and 1.5 m model SSC collider dipoles were successfully measured by the direct observation of energy flow into and out of magnets during a ramp cycle. The measurement was performed by using two double-integrating type digital volt ...
A description will be given of a new method to measure calorimetrically ac losses in superconducting samples. The boil-off gas is stored below the liquid helium level in a measuring tube. Losses in the range of 1 mW up to 100 mW can be measured with an ...
The final goal of the program is to establish standard measurement practices and a standard reference material for calibration of apparatus. In this paper the authors discuss a comparison of several techniques for measuring ac losses in superconductors. The techniques are divided into either a calorimetric or ...
A new cryostat cooled by a closed-cycle Cryomech GB-37 cryocooler for superconductor measurements at temperatures down to 20 K is described. The sample is conductively coupled to the cold stage so as to minimize vibration and thermal stresses. AC losses h...
Critical currents and AC losses of (Bi, Pb)2Sr2Ca2Cu3Ox superconducting tapes were measured in self-field as a function of temperature. The experimental data of the temperature dependence of critical current were compared with calculated results. An approach to calculating AC losses as a ...
NASA Astrophysics Data System (ADS)
A calorimeter has been developed to measure the total core loss in small samples of magnetic materials which are not suited to conventional measurement techniques. The method is similar to the helium boil-off calorimeter used in some cases to measure ac losses in ...
An AC bridge technique is described for measuring energy losses in multifilament (MF) superconductors due to alternating current flow in superconducting solenoids. Superconductivity and transient loss theory are briefly discussed, and the apparatus used to measure the ...
An empirical relation is presented which allows simple computation of volume-averaged winding fields from central fields for coils of small rectangular cross sections. This relation suggests that, in certain applications, ac-loss minimization can be accomplished by use of low winding densities, provided that hysteresis losses are independent of winding ...
The setup for measuring ac-losses in short (up to 33 cm) samples of heavy-current superconducting cables is described. A calorimetric method is used for measuring losses. The sample placed into the calorimeter is in the external pulsed field. This field w...
The report deals with hysteresis losses at 4 K measured by magnetization and complex magnetic susceptibility. The theoretical and experimental relationships between ac susceptibility and magnetization as functions of dc field were examined in terms of the...
Magnetization AC losses in striated YBCO conductors in a perpendicular applied AC magnetic field were investigated with special regard to the coupling current AC loss (CCAC). The AC loss of YBCO samples of different length L was ...
We have manufactured a small circular superconducting coil impregnated with epoxy fibreglass. The coil was wound from a Bi-2223/Ag superconducting wire and it was tested in liquid nitrogen at 77 K. Current-voltage characteristic and the AC losses of the coil were measured and compared with the measurements on the ...
The measurement of ac losses in superconducting cables by calorimetric means is necessary as a verification of electronic measurements on short high-current models and because the present method of electronic measurement is not applicable to longer cables with simultaneously applied high ...
... S2 interferometric non-contact displacement measurements ... loss and low ac stiffness so that a ... 18 From these measurements, the large signal ...
Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of ...
Reduction of ac losses in applied ac fields can be accomplished through either the creation of filaments and bridging in YBCO coated conductors or an assembly of narrow width YBCO tapes. The ac losses for each of these geometries were measured at 77 K in perpendicular ...
... AC Loss Minimisation in High Temperature Superconductors ... Extension to AC Loss Minimisation in High Temperature Superconductors ...
A calorimeter for measuring ac losses in meter-long lengths of HTS superconducting power transmission line cables is described. The calorimeter, which is based on a temperature difference technique, has a precision of 1 mW and measures single, two-phase (coupling), and three-phase losses. The ...
A report is given of calorimetric measurements of the ac losses of a small superconducting coil wound from a filament superconductor designed for low ac losses (filament phi = 8 $mu$, number of filaments 1045, CuNi barriers). The coil was pulsed with a maximum dB/dt = 480 kG/s. Further ...
Alternating current loss as a function of current and external magnetic field in commercial NbTi superconductors has been measured with an electronic wattmeter. The loss varies as the current cubed, and the increase of loss with the external magnetic fiel...
This paper describes measured AC losses of NbTi Rutherford type cable when the wide side of the cable is parallel to the field variation. In the case of a Rutherford type cable, the orientation of the cable in the magnetic field is an important factor for the interstrand coupling loss which can be dominant over ...
We are experimentally studying basic AC loss properties of IBAD/CVD-YBCO coated conductors with a copper layer for stabilizing, especially the temperature dependence of perpendicular field loss in alternating electromagnetic environments. We prepared two types of short specimens with and without a copper layer and ...
We present measurements of AC losses in Bi-2223 multi-pancakes coils with different geometries. Measurements were performed at 77 K at frequencies ranging from 50 to 1600 Hz. The losses are found to depend strongly on coil configuration and linearly increase with increasing frequency. The ...
From the time constant and the hysteresis loss measurements of the subcables, it is estimated that approximately 60% of the ac losses of the ANL 3.3 MJ coil at 6 T/s of the central field are due to the losses within the 19-strand subcable itself. The remaining 40% of the ...
DOE Information Bridge
Superconducting dipole magnets for accelerators have shown various quench current degradations and unexpected field disturbances even when they were fabricated with the same cables. Such degradations become harmful in terms of the stable operation of accelerators. The reasons for the degradations seem to be caused by AC losses due to coupling currents ...
This paper describes the design of a new test system. It is under construction now and will be used to measure the AC losses of subcable from NET conductors. A special feature of the test arrangement is that the losses will be determined while the sample carries a transport current and is at the same time subjected ...
An analysis of a new method for measuring ac losses in superconducting magnets is described. The integral of compensated voltage across the magnet and a magnet current differential are multiplied. The result of multiplication is integrated and digitally displayed. The accuracy of the electronic joulemeter based on the double ...
This report discusses the AC losses in the MICE channel magnets during magnet charging and discharging. This report talks about the three types of AC losses in the MICE magnets; the hysteretic AC loss in the superconductor, the coupling AC ...
The ac losses in superconducting vanadiura are measured before and after the implantation with 75 keV Ga-ions. A pronounced increase of the surface shielding capacity resulting in a decrease of the energy losses is observed. (auth)
From the time constant and the hysteresis loss measurements of the subcables, it is estimated that approximately 60% of the ac losses of the ANL 3.3 MJ coil at 6 T/s of the central field are due to the losses within the 19-strand subcable itself. The rema...
The magnetization loss density in stacked GdBa2Cu3O7?? coated conductor was measured using a SQUID magnetometer in a magnetic field normal to the tape surface to investigate the effect of stack on the magnetization loss. The AC loss characteristics are successfully collapsed to a single curve ...
The properties of ac hysteresis loop of a stator tooth in a 5 hp induction motor was measured and analyzed. The load increase on the motor decreased magnetic induction, however increase the minor hysteresis loops in the high induction region. This effect caused increase in the core loss. Depending on condition of the motor, the core ...
A.c. losses caused by an a.c. transport current and a transverse a.c. magnetic field during simultaneous action were measured. The loss contributions have been obtained separately. The measurements were performed on a NbTi multifilamentary wire having a ...
We present here results of our study of the 5-m-long AC transmission tine model with 1 kA current capability at 77 K. Primary attention was paid to the current characteristics and AC losses in individual tapes and in the core of the cable. The losses were measured as a function of ...
... The AC losses measured in pancake A at 3 frequencies, 54 Hz, 432 Hz and 864 Hz are shown in Figure 32. ... f = 432 Hz 900 mW 2.08 mJ 26 ...
AC losses determined with a helium boil-off calorimeter qualitatively agree with those predicted from DC magnetization measurements for a number of niobium and niobium-zirconium superconducting samples. This is consistent with a hysteretic model of AC los...
As part of an interlaboratory comparative testing program conducted in support of the Versailles Agreement on Advanced Materials and Standards (VAMAS), transverse-field dc hysteresis loss measurements were made at liquid-helium temperatures at fields of u...
Magnetization and ac susceptibility of a standard NbTi superconductor were measured as a function of longitudinal dc magnetic field. The ac-field-amplitude and frequency dependences of the complex susceptibility are examined. The magnetization is related to the susceptibility by means of a theoretical derivation based on the field ...
The phase-space of convective and diffusive fast-ion losses induced by shear Alfv�n eigenmodes has been characterized in the ASDEX Upgrade tokamak. Time-resolved energy and pitch-angle measurements of fast-ion losses correlated in frequency and phase with toroidal Alfv�n eigenmodes (TAEs) and Alfv�n cascades ...
Energy dissipation, which is also called AC loss, of a composite multifilamentary superconducting wire is one of the most fundamental concerns in building a stable superconducting magnet. Characterization and reduction of AC losses are especially important in designing a superconducting magnet for generating ...
A new cryostat cooled by a closed-cycle Cryomech GB-37 cryocooler for superconductor measurements at temperatures down to 20 K is described. The sample is conductively coupled to the cold stage so as to minimize vibration and thermal stresses. AC losses have been measured calorimetrically in several HTSC coils that ...
Since 1995 Southwire Company and Oak Ridge National Laboratory (ORNL) have jointly designed, built, and tested nine, l-m long, high temperature superconducting (HTS) transmission cable prototypes. This paper summarizes the AC loss measurements of five of the cables not reported elsewhere, and compares the losses ...
Reducing AC loss in a superconducting apparatus is one of the most important issues, and the precise measurement and estimation of AC losses are essential to reduce them. The four-terminal method is universally used as an electric measurement method of ...
Low-temperature and high-temperature superconductors are used in liquid helium (LHe) as magnets and in other applications. AC transport current loss study is important for the use of these superconductors in alternating current regimes. The measurement of AC transport current loss under LHe ...
In order to research the AC loss characteristics of a multi-layered conductor and a shield in a high temperature superconductor (HTS) cable, we prepared two short cable samples, which are the same as the 22.9 kV/50 MVA HTS-cable installed at Gochang test yard of Korea Electric Power Corporation, and attached voltage-leads to both the conductor and the ...
The successful application of superconductivity to motors and other power system components depends on the characterization and subsequent minimization of the ac loss in the superconductor used for fabrication of the component. The superconductive component, excited by an ac power source, may be exposed to large dc magnetic fields ...
An improved electronic method for measuring ac losses in superconducting cables of lengths from 1m to 10m has been developed and is described. This method compensates for phase shifts in the measuring circuit elements and for imbalance of the difference amplifier due to changes in the common mode voltage. This ...
Calorimetrically determined energy losses for a series of niobium and niobium-25 at.% zirconium samples carrying an ac transport current agreed with those calculated from hysteresis loops determined by dc magnetization measurements. The results of this study showed that the energy losses in ultra-high-purity ...
High temperature superconducting (HTS) cables with RE-123 coated conductors are expected to lower AC loss compared to that with BSCCO cable. Sumitomo Electric Industries, Ltd. (SEI) has been developing not only BSCCO wires but also RE-123 coated conductors. Recently, SEI has developed a RE-123 coated conductor with a new type of textured metal substrate ...
... YBCO Coated Conductors with Reduced AC Losses ... YBCO Coated Conductor, AC losses, RABiTS, Superconductor, Maganetic Properties ...
... Extension to AC Loss Minimisation in High Temperature Superconductors ... The transport AC loss decreases more than 3 times. ...
AFRL-PR-WP-TP-2006-208 AC LOSS REDUCTION OF YBCO ... SUBJECT TERMS AC losses, coated conductors, YBCO, multifilamentary 16. ...
A method is described for calorimetric ac-loss measurements of high-Tc superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ...
A method is described for calorimetric ac-loss measurements of high-T(c) superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ...
PubMed
The DC magnetization and AC complex magnetic susceptibilities were measured for MgB2 single crystals, unsubstituted and carbon substituted with the composition of Mg(B0.94C0.05)2. The measurements were performed in AC and DC magnetic fields oriented parallel to the c-axis of the crystals. From the DC magnetization ...
Although much research has been conducted concerning the losses of high-{Tc} superconductors, very little has concentrated on the self-field losses in an actual magnet arrangement. The coils studied in this work were designed for use as actual magnets in an industrial application. Self field loss measurements were ...
We measured and analyzed AC losses of MgB2 tape with 19 filaments surrounded by Ti barriers and embedded in copper stabilization, exposed to external magnetic field with frequencies from 30 mHz up to 1.4 Hz and amplitudes up to 0.8 T at 4.2 K. Using the measured frequency dependence of the total ...
The authors report single-phase ac loss measurements on 8, 4, and 3-layer, multi-strand, HTS prototype conductors for power transmission lines. They use both calorimetric and electrical techniques. The agreement between the two techniques suggests that the interlayer current distribution in one-meter long conductors are representative ...
The ac losses of differently twisted samples of a multifilament superconductor in a magnetic field B=B/sub s/ +B/sub 0/ sin..omega..t have been measured. The over-all loss per cycle has a maximum at a frequency f/sub m/, which shifts to smaller frequency values with decreasing twist rate. At certain frequencies a ...
... Abstract : Results are presented on the AC and DC characteristics of Wausau granite which show that excess AC losses at low temperatures are ...
The objective of the program was to study the feasibility of Nb/sub 3/Ge being used as an AC superconducting power transmission cable material. Specifically, the program was to measure AC losses in available samples of Nb/sub 3/Ge and find under what conditions the losses can be reduced to 10 ...
A novel method for AC loss measurement of a long length high Tc superconducting (HTSC) wire has been investigated. An 8 m long (Bi,Pb)2Sr2Ca2Cu3O10+x Ag clad multifilament wire was selected to prepare a special sample in which the inductive voltage induced by AC transport currents can be cancelled. Consequently the ...
Power engineering applications of HTSC tapes are often restricted by AC losses. Both direct and indirect methods have been used to measure AC losses in short samples. This paper reports on the development of a direct calorimetric method for AC loss ...
The assembly of meander shaped coated conductor tapes by the Roebel technique is a promising way to manufacture high current cables with low ac losses. The application of longitudinal striations to the single strands can be an option to create a filament structure for further possible reduction of the ac losses. ...
For the design of a high temperature superconductor (HTS) power transformer the AC loss is a critical issue because the energy is dissipated as heat in the low temperature. It is necessary to study the AC losses theoretically and experimentally. For the analysis of AC ...
Self-field ac losses were measured by the conventional ac four-probe method in biaxially aligned Y{endash}Ba{endash}Cu{endash}O tapes using polycrystalline Hastelloy tapes with textured yttria-stabilized-zirconia buffer layers. The ac losses increased in proportion to the ...
We have been developing a light weight and high efficiency superconducting traction transformer for railway rolling stock. We designed and fabricated a prototype superconducting traction transformer of a floor-mount type for Shinkansen rolling stock in 2004. We performed the type-test, the system-test, and the vibration-test. Consequently, we could verify that the transformer satisfied the ...
To achieve low ac losses in applied ac fields, YBa2Cu3Ox (YBCO) filaments were created on a RABiTS buffered substrate through solution inkjet deposition. The metal organic decomposition (MOD) solution was placed into an inkjet nozzle and filaments of widths of 100 ?m and 0.8 mm were placed on the substrate at a spacing of 50 to 100 ?m. ...
A new ac loss behaviour is observed in the superconducting state of Bi(2)Sr(2)CaCu(2)O(8) single crystals using a novel technique of measuring dissipation at radio frequencies. It is found that�the ac loss in the superconducting state is larger than that in the normal state. This ...
A series of Bi-2223 ([Bi, Pb]:Sr:Ca:Cu:O = 2:2:2:3) tapes with 37 superconducting core filaments was investigated in an attempt to correlate critical current and alternating current (AC) losses with twist-pitch. The twist-pitch of these multi-filamentary tapes which were produced by the powder-in-(Ag)tube (PIT) method varies from 8, 10, 13, 30, 50, 70 mm ...
AC losses of NbTi-Cu and NbTi-Cu-CuNi superconducting composite magnets have been measured by means of an electronic integration technique. The experimental results are presented and their qualitative comparisons are made. It is shown within our experimental range that: (1) AC losses of NbTi-Cu ...
Measurements of the total a.c. losses in an applied parallel a.c. magnetic field have been measured for Bi2223/Ag tapes with twisted and untwisted filaments. The measurements were undertaken using suitable pickup loops and a lock-in amplifier. For all frequencies (37-200 ...
... Accession Number : ADA461815. Title : AC Loss Reduction of YBCO Coated Conductors by Multifilamentary Structure. Descriptive ...
... Title : AC LOSSES OF SUPERCONDUCTING COMPOSITES WITH 8 MU-M NBTI FILAMENTS IN A DC MAGNETIC FIELD WITH A ...
A simple way to obtain true ac losses with a resonant circuit containing a superconductor, using the decay of the circuit current, is described. For the measurement a capacitor is short circuited with a superconducting cable. Energy in the circuit is provided by either charging up the capacitors with a certain voltage, or letting a dc ...
... Title : AC IMPEDANCE MEASUREMENT OF ENVIRONMENTAL ... OF INTERFACIAL IMPEDANCE MEASUREMENT ARE ... OF THE METHOD IN ...
This paper investigates the electromagnetic properties of high-temperature superconductors with a particular focus on the AC loss in coils made from YBCO superconductors. The numerical analysis and finite element modelling of the YBCO superconductors used in Cambridge�s superconducting permanent magnet synchronous motor currently in development is ...
]�[12]. It is difficult to measure ac loss and stability properties at lower temperatures primarily due to the problems are coplanar with the G10 sample holder as well as the supercon- ducting sample. A resistive heater located superconducting tape. The possibility of obtaining uniform temperature over a 15 cm long sample in 35�80 ...
E-print Network
Measurements of both the ac magnetic susceptibility in melt processed and film Y{endash}Ba{endash}Cu{endash}O and frictional losses of spinning permanent magnets levitated above Y{endash}Ba{endash}Cu{endash}O are presented. A direct correlation is observed only when large susceptibility samples are studied indicative of the importance ...
Ni-W alloys are used as the substrate in the manufacture of HTS tape via the RABiTSTM process. Theoretical work has shown that the ferromagnetism in a substrate can affect the ac losses in the superconductor. This occurs in part because of the increased magnetic permeability, which alters the magnetic induction in the superconductor and thereby the ...
The voltage V{sub ab} measured between two voltage taps a and b during magnetic flux transport in a type-II superconductor carrying current I is the sum of two contributions, the line integral from a to b of the electric field along an arbitrary path C{sub s} through the superconductor and a term proportional to the time rate of change of magnetic flux through the area bounded ...
Progress made to date on developing instrumentation and measurement methodology for studying high-voltage dielectric losses at cryogenic temperatures is detailed. The work described has been done in support of ERDA-funded ac superconducting transmission l...
The voltage V ab measured between two voltage taps a and b during magnetic flux transport in a type-II superconductor carrying current I is the sum of two contributions, the line integral from a to b of the electric field along an arbitrary path C s through the superconductor and a term proportional to the time rate of change of magnetic flux thrugh the area bounded by the ...
The magnetic properties, including ac core loss, dc hysteresis loss, eddy current loss, ac and dc permeability at 10 kG and 15 kG, and magnetic flux density at field strength 2,500 A/m, of 17 heats of fully processed, continuous-annealed low-carbon electrical steels with grain diameter from ...
AC loss can be a significant problem for any applications that utilize or produce an AC current or magnetic field, such as an electric machine. The authors investigate the electromagnetic properties of high temperature superconductors with a particular focus on the AC loss in superconducting ...
For large pulsed coils such as the ohmic heating coils, great reliability as well as low ac losses is essentially required. Therefore, the cryostability must be achieved not only within the first-level cable but within the final cable. To guarantee cryostability within the final cable, a great deal of stabilizing copper will be required, leading to the ...
The frequency characteristic of ac losses in aluminum-stabilized superconducting conductors are investigated in order to elucidate their loss mechanism under a changing transverse magnetic field. AC loss measurement is carried out for the short and straight sample conductor ...
The AC loss characteristics of a magnet-superconductor system were studied with the magnet fixed to the free end of an oscillating cantilever located near a stationary melt-textured YBCO pellet. Below a threshold AC field amplitude {approx}2Oe, the dissipation of the oscillator is amplitude-independent, characteristic of a linear, ...
Measurements of 50-Hz ac losses were performed using three characteristic NbTi coil samples with ultrafine filaments and a Cu--CuNi mixed matrix at fields up to 1 T and at 4.2 K. Critical current and quenching current densities were measured under dc and ac conditions as well as the ...
A simple model gave utilized for calculation of magnetization effects on ac loss and sextupole for Energy Doubler dipole magnets. The calculation in the simple model gave an underestimation of ac loss by about 30%. Results of computation on ac harmonics were also described.
In this study the authors examined ac losses in a multifilamentary Bi-2223/Ag superconducting tape carrying ac transport current. The tape consisting of 85 filaments was helically wound to a single-layer coil. The losses were measured at 77 K in the frequency range from 1 Hz up to 250 Hz. ...
Transport AC loss in a short length of 9/2 YBCO Roebel cable (nine 2 mm wide strands) is measured. The AC loss data are compared with those in a 5/2 YBCO Roebel cable (five 2 mm wide strands) as well as that in a single strand. All the strands composing the cables and the single strand are ...
In particle accelerators quasi-DC superconducting magnets are used to keep particles in desired tracks. The needed rapid field variations of these high energy magnets require large energy bursts. If these bursts are taken from and fed back to the utility grid, its voltage is distorted and the quality of the electricity degrades. In addition, these bursts may decrease operation life time of ...
AC losses in full length and 1.5 m model SSC collider dipoles were successfully measured by the direct observation of energy flow into and out of magnets during a ramp cycle. The measurement was performed by using two double-integrating type digital volt meters (DVM's) for current and voltage ...
AC losses in full length and 1.5 m model SSC collider dipoles were successfully measured by the direct observation of energy flow into and out of magnets during a ramp cycle. The measurement was performed by using two double-integrating type digital volt meters (DVM`s) for current and voltage ...
Transport AC loss in a short length of 9/2 YBCO Roebel cable, (i.e. with 9 � 2 mm width strands), with 0.25 mm spacers between the strands is measured. The frequency varies from 59 to 354 Hz. The result is compared with the loss for a cable without spacers between the strands. Transport AC ...
Low frequency (1 Hz) ac losses were measured in a variety of A15 superconducting wires having different fiber geometries. Field modulations ofless than or equal to 1 tesla were superimposed on a fixed background field up to 15 tesla. Losses were measured for Nb/sub 3/Sn in continuous fiber, ...
We report on measurements of the ac losses of YBa{sub 2}Cu{sub 3}O{sub 7-x} conductors on technical substrates. The samples are taken from conductors 1 m long produced with an ion beam assisted deposition step in the manufacturing process yielding 1 cm wide conductors with critical currents approaching 100 A at 77.4 K. The ...
Two 500-A class prototype high-temperature superconducting cables have been constructed by Southwire Company and tested at Oak Ridge National Laboratory (ORNL). In the first cable, no insulation was used to separate the individual HTS tapes. In the second cable, Kapton tape was used to insulate the HTS tapes between successive layers for the study of AC ...
Since the discovery of superconductivity in MgB2 many efforts have been undertaken to improve the current carrying capacity of mono- or multifilament MgB2 conductors. However, even though MgB2 conductors can be produced in geometries which easily allow twisting or cabling, the reduction of ac losses has often played a minor role, even though many technical ...
We have calculated the alternating current (ac) losses of a 114 MVA high-TC superconducting (HTS) transmission cable using an electric-circuit (EC) model. The HTS cable is fabricated by Tokyo Electric Power Company and Sumitomo Electric Industries, Ltd. The EC model is comprised of a resistive part and an inductive part. The resistive part is obtained by ...
AC losses in two, one-meter-long lengths of HTS prototype multi-strand conductors (PMC`s) are measured with a temperature-difference calorimeter. Both single-phase and three-phase losses are examined with ac currents up to 1,000 A rms. The calorimeter, designed specifically for these ...
The flux calibration of HST instruments is normally specified after removal of artifacts such as a decline in charge transfer efficiency (CTE) for CCD detectors and optical throughput degradation. This ACS ISR deals with the HRC and WFC losses in sensitivity from polymerization of contaminants on the optical surfaces. Prior to the demise of the ...
This paper reports on the AC losses of internal-tin Nb{sub 3}Sn wires measured by an isothermal calorimetric method in triangular-wave fields at ramp rates up to 1.2 T/sec and in small-amplitude ripple fields biased with dc fields up to 9 T. Measurements were made both with and without transport currents, which ...
We have measured energy loss of 0.5-2 MeV 4He ions in Mylar and Kapton foil, and hydrogenated amorphous carbon (a-C : H) films. The energy loss values or stopping powers are in good agreement with the calculation from Ziegler's cores and bonds (CAB) stopping model. No significant physical state (gas-solid) effect ...
Tests have recently been performed at Fermilab in order to measure the energy losses due to eddy currents and iron and superconductor magnetization. These measurements were performed on six 1.5m long model magnets and eight 15m long full scale collider dipole magnets. AC losses were ...
Critical-current density, upper critical field, and hysteresis ac losses have been evaluated for a large (100-m long) sample of in situ formed Cu-Nb/sub 3/Sn composite with superconducting volume fraction lambdaapprox. =0.23. The magnetic field dependence of the critical current, measured in wire and tape samples of different ...
The cable in conduit conductors for the various ITER coils are required to function under pulse conditions and fields up to 13 T. A parametric study, restricted to a limited variation of the reference cable lay out, is carried out to clarify the quantitative impact of various cable parameters on the coupling loss and to find realistic values for the coupling ...
Magnetism can affect losses in superconducting coils in two ways. First, there is magnetic loss ('core loss'). This can be separately measured as a function of magnetic induction in the material of interest (usually the substrate on which a superconducting film is grown). One can then find the fields in the coil ...
The power supply design of the (gamma)(sub f) - jump system in FNAL Main Injector uses a resonant circuit. A critical design parameter is the ac losses of the beam tube in a pulsed quadrupole. This paper gives an analysis to this problem. An equivalent ci...
at the fiber-cavity junction and we take the upper sign for ac[6]. The normalized trasmission of the resonator electric-field cavity energy along with a linear fit. where the upper sign is taken in the undercoupled
The authors measured AC losses of AC multifilamentary wires (NbTi and Nb{sub 3}Sn) and a cable of (6+1) configuration due to transport currents in an AC external magnetic field at 50Hz. They also studied the stabilities of the NbTi and Nb{sub 3}Sn wires and the cable. The Nb{sub 3}Sn ...
The Oak Ridge National Laboratory (ORNL) is collaborating with Waukesha Electric Systems (WES) to continue development of HTS power transformers. For compatibility with the existing power grid, a commercially viable HTS transformer will have to operate at high voltages in the range of 138 kV and above, and will have to withstand 550-kV impulse voltages as well. Second-generation (2G) YBCO coated ...
We have measured the frequency dependent magnetic ac loss in a five strand Roebel cable with 2 mm wide non-insulated strands and a transposition length of 90 mm. The cable is made from 12 mm wide SuperPower YBCO (yttrium barium copper oxide) coated conductor tape with a 20 �m thick surrounding copper stabilizer layer. The ...
A study has been made of ac loss characteristics of type-II superconductors due to hysteresis losses in the superconducting material and eddy current losses in the normal matrix in the absence of an applied field. Losses were measured for Nb$sub 3$Sn tapes, a Nb ...
Eastham and Rhodes published results of loss measurements on transposed superconducting NbTi cables and concluded basing on an extrapolation to very large numbers of wires that transposed superconductors could be used favorably in cables for power transmission. There are some reasons to question the correctness of their extrapolation. ...
Calorimetric measurements of the losses of a superconducting coil wound from a moderately twisted multifilamentary superconducting wire have been made with a coil current consisting of a direct current and a superimposed ac component at frequencies between 1 and 100 Hz. There exists a frequency range where the ...
Results are presented of investigations on the determination of ac/dc resistance ratios of high and extra high voltage pipe-type cables with large cross-section segmental conductors. The measurements included 115, 345 and 765 kV cables with copper and alu...
We fabricated and characterized the Bi2223 tape with Al2O3 as interfilamentary resistive barriers for the filament decoupling and also for the reduction of AC losses under AC external magnetic field. The tapes with thin Al2O3 barrier layers around the Bi2223 filaments were prepared by using a standard powder-in-tube (PIT) method. Al2O3 ...
This report discusses the AC losses in the MICE channelmagnets during magnet charging and discharging. This report talks aboutthe three types of AC losses in the MICE magnets; the hysteretic AC lossin the superconductor, the coupling AC loss in the ...
Hysteretic losses were measured as a function of temperature from 4 to 20 exp 0 K in bulk samples of CVD-prepared Nb sub 3 Ge. The measurements were performed on samples which contained differing amounts of second phase Nb sub 5 Ge sub 3 and which have be...
A C loss measurement results are reported on the NT-50 multifilament superconductors in magnetic fields up to 3T which change with velocity up to 1.5 T/s. Superconductors, proposed for the first model pulsed dipoles, tested in the Laboratory of High Energ...
Researches and developments on a superconducting fault current limiting (SFCL) system have been done for several decades. The SFCL system, which is using a high temperature superconducting (HTS) conductor such as Bi-2212 bulk and YBCO film, has recently become technically available. In this work, we are developing a 22.9 kV/25 MVA SFCL system for a power distribution network. A Bi-2212 bulk SFCL ...
Page 1. AFRL-PR-WP-TP-2006-210 LOW AC LOSS STRUCTURES IN ... 2, JUNE 2005 2827 Low AC Loss Structures in YBCO Coated Conductors ...
This paper discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjected ...
This lecture discusses the physics of ac losses in type-II superconductors and in multifilamentary superconducting-normal composite conductors. As an introduction, the ac eddy-current losses in a homogeneous normal conducting cylindrical specimen subjecte...
While the performance of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO)-based coated conductors under dc currents has improved significantly in recent years, filamentization is being investigated as a technique to reduce ac loss so that the 2nd generation (2G) high temperature superconducting (HTS) wires can also be utilized in various ac power ...
In a three-phase tri-axial cable, the magnetic interaction between the phases makes the loss measurement by an electromagnetic method very complex. We developed the theoretical background showing that three-phase AC loss measurements by the electromagnetic method are, in principle, possible. We ...
The authors have investigated the AC losses in coils with NbTi superconducting wires. They have used the multiple stacking procedure to prepare the wires, varying in filament size from 10/mu/m to 0.07/mu/m. Three kinds of wires with 0.07/mu/m filament were specially fabricated to estimate the proximity effect on AC ...
A theoretical and experimental study is presented of the influence of thermally activated flux creep on the ac response of a type II superconductor in the mixed state. The theory describes the ac response of a cylindrical superconductor in the mixed state in an axial dc magnetic field and a superposed parallel ac field of low amplitude ...
The results of ac dielectric-loss measurements on bushings mounted in certain three-phase transformers, if not performed in accordance with the prescribed procedure, can deviate significantly from the correct values. An investigation of the incorrect procedure has shown that the capacitive couplings between adjacent windings and the ...
The voltage V_ab measured between two voltage taps a and b during magnetic flux transport in a type-II superconductor carrying current I is the sum of two contributions, the line integral from a to b of the electric field along an arbitrary path Cs through the superconductor and a term proportional to the time rate of change of magnetic flux through the area bounded by the ...
Low AC loss and high current density NbTi/Cu/CuNi double stage cabling superconductor for quick response superconducting generator (SCG) has been developed. Its characteristics were measured by short sample and several coil models. The critical current of 14kA at 6T and the AC loss of ...
... Accession Number : ADA481255. Title : YBCO Coated Conductors with Reduced AC Losses. Descriptive Note : Final technical rept. ...
... Accession Number : ADA346511. Title : Program to Study AC Loss in High-Tc Superconductors. Descriptive Note : Final technical rept. ...
... Title : Low AC Loss Structures in YBCO Coated Conductors With Filamentary ... Personal Author(s) : Barnes, Paul N. ; Levin, George A. ; Varanasi ...
... Abstract : This report results from a contract tasking University of Cambridge as follows: The contractor will investigate: 1) AC losses of appropriate ...
... Title : Critical Currents and AC Losses in Model YBCO ... HALL EFFECT, ELECTRIC FIELDS, ALTERNATING CURRENT, OXIDES, COPPER ...
... Using the two-dimensional FEM model for electromagnetic field analysis of coated conductors, the AC losses at various conditions were calculated ...
... Title : AC LOSSES IN A MULTIFILAMENTARY NB3AL/CU COMPOSITE SUPERCONDUCTOR MADE BY A JELLY ROLL PROCESS. ...
The voltage V(sub ab) measured between two voltage taps a and b during magnetic flux transport in a type-II superconductor carrying current I is the sum of two contributions, the line integral from a to b of the electric field along an arbitrary path C(su...
The large cross-sectional aspect ratio of YBCO coated conductors leads to a large magnetization loss in an AC transverse magnetic field. In this work, the magnetization loss of a multifilamentary YBCO coated conductor was studied experimentally. A 100 mm length of striated multifilamentary YBCO coated conductor was prepared where the ...
Since a 100 m, 22.9 kV/50 MVA high temperature superconductor (HTS) cable system was installed at the Gochang test yard of Korea Electric Power Corp. (KEPCO) in 2005, a long-term test has been performed. In this paper, the transport characteristics of the KEPCO HTS cable system were examined by the electrical and calorimetric methods. To analyze the shield current in this system, an equivalent ...
Calorimetric and magnetic measurements of AC loss in Nb3Sn Rutherford cables were accompanied by magnetic measurements of persistent-current (hysteretic) loss in strands extracted from those cables. From the cable-loss measurements it is shown that the ...
The fill factor losses in Cu/sub 2/S/CdS solar cell devices are discussed in terms of series resistance, interface collection, and diode factor contributions to reducing the fill factor below that of an ideal diode. AC techniques have been used in the past to deduce the losses due to interface collection. It is shown that these methods ...
Impedance spectroscopy has been used to study the effect of kaolinite grain sizes on the AC electrical properties of kaolinite/polystyrene composites under different temperatures and applied frequencies. Impedance measurements were performed on prepared composites containing 20% kaolinite mineral of grain sizes 63, 106, 212, and 300 ?m in addition to neat ...
Superconducting transmission cables are important for increasing the capability of electricity networks. We analysed monolayer power transmission cable based on high-temperature superconductors, and we propose a new way to improve its performance in this paper. We studied two important parameters of this cable�critical current and AC loss. For the former ...
The power supply design of the {gamma}{sub f} - jump system in FNAL Main Injector uses a resonant circuit. A critical design parameter is the ac losses of the beam tube in a pulsed quadrupole. This paper gives an analysis to this problem. An equivalent circuit model based on the impedance measurement was established. The ...
We performed a round robin test to measure AC losses in Bi-2223 Ag-sheathed tapes with saddle-shaped pickup coils in an alternating perpendicular magnetic field at liquid nitrogen temperature. Two laboratories participated in the round robin test with each system of the pickup coil and the measurement circuit. ...
The Low Energy Demonstration Accelerator (LEDA) facility located at Los Alamos National Laboratory (LANL) accelerates protons to an energy of 6.7 MeV and current of 100 mA operating in either a pulsed or cw mode. Two types of current measurements are used. The first is an AC or pulsed-current measurement which uses three LANL built ...
A project was conducted to evaluate measures for controlling loss of asbestos fibers from asbestos-cement (A/C) water distribution pipe under aggressive water conditions. During Phase 1, water quality data were analyzed for the distribution system of Bell...
Conventional methods for calculating electricity losses in pipe-type cable systems rely heavily on data measured in lower-voltage systems in the 1950s. With the new technique developed in this study, engineers can compute power losses more precisely for cables of various configurations and voltage ratings.
A project was conducted to evaluate measures for controlling loss of asbestos fibers from asbestos-cement (A/C) water distribution pipe under aggressive water conditions. During Phase 1, water quality data were analyzed for the distribution system of Bellevue, Washington, which r...
EPA Science Inventory
Iron doped amorphous carbon (a-C: Fe) films on n-Si substrates were fabricated by pulse laser deposition technique. Barrier heights of the heterojunctions, measured in the electrical methods, were found to decrease gently below 300 �C and then increase anomalously thereafter. An interface energy band model was proposed to interpret the band structure of ...
The influence of the geometrical parameters on the behavior of the AC losses in multifilamentary AG-BSCCO(2223) tapes is being more and more evident. Recently, the effects of configurational parameters like the ratio between the overall width and thickness of tapes without barriers as well as their precise arrangements have been put in evidence either ...
Two ac dipoles with vertical and horizontal magnetic field have been proposed at RHIC for applications in linear and non-linear beam dynamics and spin manipulations. A magnetic field amplitude of 380 Gm is required to produce a coherent oscillation of 5 times the rms beam size at the top energy. We take the ac dipole frequency to be 1.0% of the revolution ...
Sb2Te3 single crystals have been grown by Travelling Heater Method. EDAX was carried out for confirmation of constituent elements. By the measurements of Dielectric constant (k) and dielectric loss (tan?), we are able to understand various polarization mechanism in the grown crystals such as space charge polarization, orientational polarization of dipoles ...
This paper introduces different AC (Admission Control) algorithms implemented in the multi-service AQUILA QoS IP network [4]. They are aimed at regulating volume of submitted traffic inside network services designed for handling real-time streaming VBR (Variable Bit Rate) and elastic (more precisely, produced by greedy TCP sources) flows. For streaming flows, the MBAC ...
We have investigated the frequency dependent contributions to the magnetic ac loss in a 10 strand Roebel cable with 2 mm wide non-insulated strands and a transposition length of 90 mm. This cable is made from 40 mm wide YBCO coated conductor tape manufactured by AMSC and stabilized by electroplating 25 �m thick copper on either side prior to the ...
... TERMS magnetization losses, superconductor, YBCO coated ... of coated super- conductors in demanding ac ... Theory of Superconductors Tay- lor and ...
... ALTERNATING CURRENT, CRITICAL TEMPERATURE, LOSSES, HYSTERESIS, UNITED KINGDOM, YTTRIUM BARIUM COPPER OXIDES. ...
... SUPERCONDUCTORS, *ELECTRIC FIELDS, *ALTERNATING CURRENT ... SURFACE PROPERTIES, THINNESS, SCALAR FUNCTIONS, LOSSES ...
... The main obstacle to the use of superconductors in electrical machines in ... superconducting cylinder (ie the losses in the superconductor plus the ...
... MATHEMATICAL MODELS, ALTERNATING CURRENT, LOSSES, MAGNETIZATION, COPPER OXIDES, YTTRIUM OXIDES, BARIUM OXIDES ...
In electrical power devices, ac losses from a superconductor is a primary factor which determines their usefulness as commercial power equipment. For this reason, extensive studies have been carried out on the losses of Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}/Ag, [Bi(2223)/Ag], tapes. These studies were mostly limited to a single ...
In this paper an improved measurement system for experimental assessment of magnetic fluid losses is presented. When fluid is exposed to AC magnetic field, three different losses mechanisms are active; relaxation, hysteresis and resonance mechanism. In this paper not individual contributions where studied but ...
... Title : THE USE OF AC FIELD MEASUREMENTS TO DETERMINE THE SHAPE AND SIZE OF A CRACK IN A METAL. Corporate Author : ...
... Abstract : MEASUREMENT OF THE AC MAGNETIC SUSCEPTIBILITY OF A LARGE, WEAKLY MAGNETIC OBJECT HAS ADVANTAGES OVER DC ...
... MAGNETIC SENSOR FOR A DIRECT MEASUREMENT OF THE AC INITIAL PERMEABILITY OF FULL WAFER SOFT MAGNETIC FILMS (UP TO ...
... Title : Measurement of Low Corrosion Rates: Comparison of ac Impedance and Thin Layer Activation Methods,. Corporate Author : ...
The new heavy ion synchrotron facility proposed by GSI will have two superconducting magnet rings in the same tunnel, with rigidities of 300T{center_dot}m and 10OT{center_dot}m. Fast ramp times are needed. These can cause problems of ac loss and field distortion in the magnets. For the high energy ring, a lm model dipole magnet has been built, based on the ...
Multifilamentary Bi2223 tapes are exposed to the longitudinal magnetic field as well as the transverse one in some electrical power apparatuses such as multilayer power transmission cables. Here, we define the longitudinal and transverse magnetic fields as the field components parallel and perpendicular to the tape axis, respectively. If the filament-bundle is twisted, it can couple to the ...
