advertisement
Electric Motors and Drives
Introduction
 |
| Electric Motors and Drives |
Electric motors are so much a part of everyday life that we seldom give them a second thought. When we switch on an electric drill, for example, we confidently expect it to run rapidly up to the correct speed, and we do not question how it knows what speed to run at, or how it is that once enough energy has been drawn from the supply to bring it up to speed, the power drawn falls to a very low level. When we put the drill to work it draws more power, and when we finish the power drawn from the mains reduces automatically, without intervention on our part.
advertisement
The humble motor, consisting of nothing more than an arrangement of copper coils and steel laminations, is clearly rather a clever energy converter, which warrants serious consideration. By gaining a basic understanding of how the motor works, we will be able to appreciate its potential and its limitations, and (in later chapters) see how its already remarkable performance can be further enhanced by the addition of external electronic controls.
Electricity & Controls for HVAC/R
advertisement
Table of Content
1 ELECTRIC MOTORS
Producing Rotation 2
Magnetic Circuits 7
Torque Production 16
Specific Loadings and Specific Output 21
Energy Conversion – Motional EMF 25
Equivalent Circuit 30
General Properties of Electric Motors 39
2 POWER ELECTRONIC CONVERTERS FOR MOTOR DRIVES
Voltage Control – D.C. Output from D.C. Supply 47
D.C. from A.C. – Controlled Rectification
Transient Behaviour – Current Surges
Shunt, Series and Compound Motor
Four-Quadrant Operation and Regenerative Braking
Toy Motors
3 CONVENTIONAL D.C. MOTORS
Torque Production 84
Motional E.M.F. 90
D.C. motor – Steady-State Characteristics 95
Transient Behaviour – Current Surges 107
Shunt, Series and Compound Motors 111
4 D.C. MOTOR DRIVES
Thyristor D.C. Drives – General 134
Control Arrangements for D.C. Drives 148
Chopper-Fed D.C. Motor Drives
D.C. Servo Drives
Digitally Controlled Drives
5 INDUCTION MOTORS – ROTATING FIELD, SLIP AND TORQUE
The Rotating Magnetic Field 170
Torque Production 183
Influence of Rotor Current on Flux 191
Stator Current-Speed Characteristics 193
Electric Motors and Drives
ReplyDelete