4EE3 ELECTRICAL MACHINE S-II

Unit-1

Introduction:

General equation of inducted emf, AC armature windings: concentric and

distributed winding, chording, skewing, effect on induced emf. Armature and field mmf, effect

of power factor and current on armature mmf, harmonics. Rotating fields.

Unit-2

Induction Motors:

Construction of squirrel cage & slip ring induction motor, basic principles,

flux and mmf waves, induction motor as a transformer. Equivalent circuits, torque equation,

torque-slip curves, no load & block rotor tests, circle diagram, performance calculation. Effect

of rotor resistance. Cogging, Crawling. Double cage squirrel cage induction motor, induction

generator, induction regulator.

Unit-3

Starting & Speed Control of Induction Motors:

Various methods of

starting & speed

control of squirrel cage & slip ring motor, cascade connection, braking.

Single-Phase Induction Motor:

Revolving field theory, starting methods, equivalent circuits.

Unit-4

Synchronous Generator:

Construction, types, excitation systems, principles. Equation of

induced emf, flux and emf waves, theory of cylindrical rotor and salient pole machines, two-

reactance theory, phasor diagrams, power developed, voltage regulation, OC & SC tests, zero

power factor characteristics, potier triangle and ASA method of finding voltage regulation,

synchronization, parallel operation, hunting and its prevention.

Unit-5

Synchronous Motors:

types, construction, principle, phasor diagrams, speed torque

characteristics, power factor control, V-curves, starting methods, performance calculations,