Electric Motors and Drives - 1st Edition - ISBN: 9780434907953, 9781483105277

Electric Motors and Drives

1st Edition

Fundamentals, types and applications

Authors: Austin Hughes
eBook ISBN: 9781483105277
Imprint: Newnes
Published Date: 1st January 1990
Page Count: 316
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Electric Motors and Drives: Fundamentals, Types and Applications provides information regarding the inner workings of motor and drive system. The book is comprised of nine chapters that cover several aspects and types of motor and drive systems. Chapter 1 discusses electric motors, and Chapter 2 deals with power electronic converters for motor drives. Chapter 3 covers the conventional d.c. motors, while Chapter 4 tackles inductions motors – rotating field, slip, and torque. The book also talks about the operating characteristics of induction motors, and then deals with the inverter-fed induction motor drives. The stepping motor systems; the synchronous, switched reluctance, and brushless d.c. drives; and the motor/drive selection are also covered. The text will be of great use to individuals who wish to familiarize themselves with motor and drive systems.

Table of Contents


1 Electric Motors


Producing Rotation

Electromagnetic Force

Magnetic Flux and Flux Density

Force on a Conductor

Magnetic Circuits

Magnetomotive Force (MMF)

Electric Circuit Analogy and Reluctance

The Air-Gap

Air-Gap Flux Densities


Magnetic Circuits in Motors

Torque Production

Magnitude of Torque


Specific Loadings and Specific Output

Specific Loadings

Torque and Motor Volume

Specific Output Power - Importance of Speed

Motional EMF

Power Relationships - Stationary Conditions

Power Relationships - Conductor Moving at Velocity V

Equivalent Circuit

Motoring Condition

Behavior without Load

Behavior when Loaded

Relative Magnitudes of V, E and Efficiency

General Properties of Electric Motors

Operating Temperature and Cooling

Torque per Unit Volume

Power per Unit Volume - Importance of Speed

Size Effects - Specific Torque and Efficiency

Efficiency and Speed

Rated Voltage

Short-Term Overload

2 Power Electronic Converters for Motor Drives


General Arrangement of Drive

Voltage Control - D.C. Output from D. C Supply

Switching Control

Transistor Chopper

Chopper with Inductive Load - Over-Voltage Protection

Features of Power Electronic Converters

D.C. from A.C. - Controlled Rectification

The Thyristor and Controlled Rectification

Single Pulse Rectifier

Single-Phase Fully Controlled Converter - Output Voltage and Control

3-Phase Fully Controlled Converter

Firing Circuits

A.C. from D.C. - Inversion

Single-Phase Inverter

Output Voltage Control

Sinusoidal PWM

3-phase Inverter

Forced and Natural Commutation

Converter Waveforms and Acoustic Noise

Cooling of Power Switching Devices

Thermal Resistance

Arrangement of Heat-Sinks and Forced-Air Cooling

Cooling Fans

3 Conventional D.C. Motors


Torque Production

Function of the Commutator

Operation of the Commutator - Interpoles

Motional E.M.F.

Equivalent Circuit

D.C. Motor - Steady-State Characteristics

No-Load Speed

Performance Calculation - Example

Behavior when Loaded

Base Speed and Field Weakening

Transient Behavior - Current Surges

Shunt, Series and Compound Motors

Shunt Motor - Steady-State Operating Characteristics

Series Motor - Steady-State Operating Characteristics

Universal Motors

Compound Motors

Four Quadrant Operation and Regenerative Braking

Full Speed Regenerative Reversal

Dynamic Braking

4 D.C. Motor Drives


Thyristor D.C. Drives

Motor Operation with Converter Supply

Motor Current Waveforms

Converter Output Impedance: Overlap

Four-Quadrant Operation and Inversion

Single-Converter Reversing Drives

Double Converter Reversing Drives

Power Factor and Supply Effects

Control Arrangements for D.C Drives

Current Control

Torque Control

Speed Control

Overall Operating Region

Armature Voltage Feedback and IR Compensation

Drives without Current Control

Chopper-Fed D.C. Motor Drives

Performance of Chopper-fed D.C. Motor Drives

Torque-Speed and Control Arrangements

Developments in Industrial D. C Drives

D.C Servo Drives


Position Control

5 Induction Motors-Rotating Field, Slip and Torque


Outline of Approach

The Rotating Magnetic Field

Production of Rotating Magnetic Field

Field Produced by Each Phase-Winding

Resultant Field

Direction of Rotation

Main (Air-Gap) Flux and Leakage Flux

Magnitude of Rotating Flux Wave

Excitation Power and VA


Torque Production

Rotor Construction


Rotor Induced E.M.F., Current and Torque

Influence of Rotor Current on Flux

Reduction of Flux by Rotor Current

Stator Current-speed Characteristics

6 Operating Characteristics of Induction Motors

Methods of Starting Cage Motors

Star/Delta (Wye/Mesh) Starter

Autotransformer Starter

Resistance or Reactance Starter

Solid-State Soft Starting

Run-up and Stable Operating Regions

High Inertia Loads - Overheating

Steady-State Rotor Losses and Efficiency

Steady-State Stability - Pull-out Torque and Stalling

Torque-Speed Curves - Influence of Rotor Parameters

Cage Rotor

Double Cage Rotors

Deep Bar Rotors

Starting and Run-up of Slip-ring Motors

Influence of Supply Voltage on Torque-Speed Curve

Generating and Braking

Generating Region - Overhauling Loads

Plug Reversal and Plug Braking

Injection Braking

Speed Control

Pole-Changing Motors

Voltage Control of High-Resistance Cage Motors

Speed Control of Wound-Rotor Motors

Power-Factor Control and Energy Optimization

Slip Energy Recovery (Wound-Rotor Motors)

Single-Phase Induction Motors

Principle of Operation

Capacitor-Run Motors

Split-Phase Motors

Shaded-Pole Motors

7 Inverter-Fed Induction Motor Drives


Comparison with D.C. Drive

Inverter-Fed Induction Motors

Steady-State Operation - Importance of Achieving Full Flux

Torque-Speed Characteristics - Constant V/f Operation

Permissible Range of Continuous Operation

Limitations Imposed by the Inverter - Constant Power and Constant Torque Regions

Limitations Imposed by Motor

Control Arrangements for Inverter-Fed Drives

Open-Loop Speed Control

Closed-Loop Speed Control

Vector Control

8 Stepping Motor Systems


Open-Loop Position Control

Generation of Step Pulses and Motor Response

High Speed Running and Ramping

Principle of Motor Operation

Variable Reluctance Motor

Hybrid Motor


Motor Characteristics

Static Torque-Displacement Curves


Step Position Error and Holding Torque

Half Stepping

Step Division - Mini-Stepping

Drive Circuits and Steady-State Characteristics

Requirements of Drive

Pull-Out Torque under Constant-Current Conditions

Drive Circuits and Pull-Out Torque-Speed Curves

Resonances and Instability

Transient Performance

Step Response

Starting from Rest

Optimum Acceleration and Closed-Loop Control

9 Synchronous, Switched Reluctance and Brushless D.D. Drives


Synchronous Motors

Excited Rotor Motors


Power Factor Control

Permanent-Magnet Synchronous Motors

Hysteresis Motors

Reluctance Motors

Controlled-Speed Synchronous Motor Drives

Open-Loop Inverter-Fed Synchronous Motor Drives

Self-Synchronous (Closed-Loop) Operation

Operating Characteristics and Control

Switched Reluctance Motor Drives

Principle of Operation

Power Converter

Characteristics and Control

Brushless D.C. Motors

Characteristics and Control

10 Motor/Drive Selection


Power Range for Motors and Drives

Maximum Speed and Speed Range

Load Requirements - Torque-Speed Characteristics

Constant-Torque Load

Fan and Pump Loads

General Application Considerations

Regenerative Operation and Braking

Duty Cycle and Rating

Enclosures and Cooling

Dimensional Standards

Supply Interaction and Harmonics

Further Reading



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© Newnes 1990
eBook ISBN:

About the Author

Austin Hughes

Affiliations and Expertise

Department of Electrical and Electronic Engineering, University of Leeds, UK

Ratings and Reviews