motor speed control, consider the use of alternating current (AC) variable frequency drive ... AC variable frequency systems for motor speed control offer ...

Power dissipation is ac induction motor is reduced by circuit that lowers applied voltage when motor

The objectives of this program for an improved ac motor controller for battery powered urban electric passenger vehicles were: the design, fabrication, test, evaluation and cost analysis of an engineering model controller for an ac induction motor drive s...

Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis

This book: outlines such new analytical tools as phase segregation and decaying-vector symmetrical component methods, explains new control methods for superior applications of AC motors, details practices that suppress and prevent occurrence of transient phenomena, provides techniques for improving control ...

A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch ...

A variable frequency inverter is described 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 o...

An ac motor controller for an induction motor electric vehicle drive system was designed, fabricated, tested, evaluated, and cost analyzed. A vehicle performance analysis was done to establish the vehicle tractive effort-speed requirements. These requirem...

Recent advances in speed control of ac motors are making it possible to replace dc motors by ac motors. The most important state variable of ac motor used for speed control is the torque. Synchronous ...

This book is divided into: technology of energy-efficient motors, selection and application of energy-efficient motors, efficiency labeling and verification, power factor, single-phase and synchronous motors, adjustable speed drives, and ac motor control and protection. ...

This paper presents the potential electrical energy efficiency improvements for utilizing alternating current (AC) motors controlled by variable frequency drives (VFD) in place of direct current (DC) motors to drive plastic extrusion machines. A brief background on the extrusion process is presented along with ...

Techniques for energy conservation of reducing losses in ac motor driven systems were compared. The impact on electric utility system as a harmonics, power factor of operation, and Electro Magnetic Interference (EMI) is considered. The techniques evaluated are: (1) the NASA Power Factor Controller, a simple device for reducing power ...

Sep 1, 1982 ... Subject Terms: ALTERNATING CURRENT; BATTERY CHARGERS; CONTROLLERS; ELECTRIC BRIDGES; ELECTRIC CHOPPERS; ELECTRIC MOTOR VEHICLES; HARMONICS; ...

The motor to be controlled is powered by two energizing circuits. Each of the circuits consists of an A.C. supply connected in series through a current control, such as a thyratron tube, to the motor. One of the energizing circuits provides a driving powe...

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...

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. his energy optimizer is complemented by a sensorless speed controller that maintains motor shaft rev...

controllers can be designed, such as the ac�synchronous motor and, most importantly, the ac�induction motor optimal control as a function of vehicle speed. By assuming the motor to be operating at steady motor optimal ...

Featuring low maintenance requirements and high durability, a direct-digital-controlled AC servo-motor drive system employing a synchronous motor with a permanent-magnetic rotor as well as an induction motor has been developed. This system attains flexibl...

reduced tailpipe emissions. Researchers are testing key power components, including motor controllers, AC to DC converters, and inverters that condition the electrical signal...

The power factor controller (PFC) is a solid state electronic device that reduces excessive energy waste in ac induction motors. The significance of the PFC lies in the fact that nearly a billion induction motors are used daily. The PFC is applicable to both single phase and three phase induction ...

Direct AC/AC converters have been studied due to their potential use in power converters with no DC-link capacitor, which can contribute to the miniaturization of power converters. However, the absence of a DC-link capacitor makes it difficult to control the AC motor during power interruption. First, this paper ...

A shearer-type mineral winning machine has three-phase A.C. Motors on its main body for driving cutting drums and for propelling the machine along a mineral face. The frequency of the A.C. power supplied to the motor which serves to move the machine is varied and controlled in dependence on the ...

Various reactor control schemes which give rise to completely static control can be applied to large wound-rotor and squirrel-cage motors. Many different starting and running requirements can also be satisfied. (C.J.G.)

This paper presents and discusses techniques for energy conservation by reducing losses in ac motor driven systems, proposed by the technical community in response to surging cost of energy. An important aspect considered is the impact on electric utility systems in terms of harmonics and power factor of operation. The techniques evaluated in this paper ...

A sensorless field oriented control scheme for surface mount permanent magnet ac (PMAC) motor with split phase stator windings is presented. This motor is obtained by splitting the phase windings of a conventional three phase motor. The six-phase motor, however is run as a ...

The motor-generator power supply and control circuits for the NIMROD synchrotron are described. These components are used to obtain pulsed and steady magnetic fields using magnet models AC1, 2, and 3. (auth)

The use of an SCR-controlled power system on an offshore drilling rig has lead to an increased acceptance of high technology equipment. Such equipment increases drilling productivity, reduces maintenance, and improves reliability. Most new rigs now have AC squirrel cage motors, brushless AC generators, silicon ...

This curriculum guide provides competency-based instructional materials for training in the field of industrial electricity. Materials are not geared to a specific grade level and may be used with secondary and postsecondary students as well as part- and full-time adult students. The guide includes three sections and ten instructional units. Each unit of instruction consists of eight basic ...

This paper discusses the characteristics of the concept and includes discussion of the system constraints, including traction battery constraints, and brief descriptions of the major subsystems being developed. The components discussed include: the system controller, dc to ac inverter, an internal permanent magnet ac ...

Electric motor manufacturers are marketing electronically controlled, direct current (dc), brushless motors that can be as much as 60% more efficient than alternating current (ac) motors when they are running at reduced speeds. The electronic controls vary the actual ...

... using silicon controlled rectifiers (SCR) with induction motor loads ... feet away from the ac generator with little ... The choice of three-phase or two-phase ...

on the traditional use of golf-cart style batteries in electric vehicles and .... integrated circuitry decreases and general interest in electric vehicles ...

... Specific projects involved the permanent magnet synchronous, switch reluctance, induction and DC motors, power electronics devices, including ...

...AC-powered adjustable hospital bed is a device intended for medical purposes that consists of a bed with a built-in electric motor and remote controls that can be operated by the patient to adjust the height and surface contour of the bed....

Test data are presented and the design of a high-efficiency motor/generator controller at NASA-Lewis for use with the Space Station power system testbed is described. The bidirectional motor driver is a 20 kHz to variable frequency three-phase ac converter that operates from the high-frequency ...

The objectives of this program for an improved ac motor controller for battery powered urban electric passenger vehicles were: the design, fabrication, test, evaluation and cost analysis of an engineering model controller for an ac induction motor drive system, the ...

This patent describes an improved energy efficient control system in conventional air-conditioning and heat pump system. The systems normally including a compressor means, a compressor motor for operating the compressor means, a compressor contactor for turning the compressor motor on and off, an evaporator means, a conditioned air ...

An electric positional control apparatus is designed for reactor control rods so that the required amount of control apparatus is reduced. The apparatus includes a plurality of positional-type motors, a low-frequency a-c voltage generator, and a control circuit that ...

Techniques for energy conservation of reducing losses in ac motor-driven systems proposed by the technical community in response to surging cost of energy are evaluated and compared. Report objectives are to provide better understanding of underlying principles and to evaluate technical and economic viability of these techniques for various applications. ...

An AC tracking system for motor speed stabilization is described. The system useds tachometer generators on the shaft of the motor as sources of control signals with an adder and reversing and non-reversing amplifiers as signal processors. The system yiel...

Converter-fed synchronous-motor drive systems provide optimum control of medium- and high-speed large-capacity AC motors. The article reports on recent technical advances in control methods, large-capacity thyristor converters, and motors, and introduces ...

The paper discusses the fuzzy logic control (FLC) of electric motors, being investigated under the sponsorship of the U.S. EPA to reduce energy consumption when motors are operated at less than rated speeds and loads. lectric motors use 60% of the electrical energy generated in t...

Offering an introduction to power electronics, this text considers the topics of analogue electronics, electric motor control, and adjustable speed electrical drives, both a.c. and d.c. Up-to-date in its coverage of this rapidly developing field, the book examines such topics as controlled bridge rectifiers and ...

The complete report is divided into three parts as follows: (1) This report combines a historical perspective with a current assessment of the use of power factor controllers for three-phase ac motor energy savings. The power factor controller (PFC) is a ...

An electric motor using thyristor switches to allow connection to an ac supply voltage is described. The thyristor switching is accomplished in part, by the use of a sensor which notes and uses relative positions of the magnetic fields of the armature and of the field to change the gate voltage applied to the thyristor and, in part, by the ...

Urban rail propulsion systems in use around the world are carefully discussed in this single-source book. It especially spotlights the status of advanced propulsion systems and their electromagnetic compatability characteristics. It presents actual operating experience of transit systems. Systems covered include: Cam controlled and chopper controlled dc ...

Traditionally, fans and pumps have been designed to be capable of handling the maximum demand of the system in which they are installed. However, quite often the actual demand can vary and it can be much lower than the original design capacity. These situations have been corrected in the past through additions of outlet dampers to fans or throttling valves to pumps. While these can be effective ...

The paper describes briefly the following components of hydrogen-electric power drives: chilled hydrogen gas tank, liquid oxygen tank, fuel cell bank, dc/ac converter, ac drive motors, solid-state ac speed control, dc sputter-ion vacuum pumps, steam turbine generator, and steam condenser. Uses ...