3EE4 ELECTRICAL MACHINES-I

Unit-1

Electromechanical Energy Conversion:

Basic principles of electromechanical energy

conversion. Basic aspects and physical phenomena involved in energy conversion. Energy

balance.

Unit-2

DC generators

: Construction, Types of DC generators, emf equation, lap & wave windings,

equalizing connections, armature reaction, commutation, methods of improving commutations,

demagnetizing and cross magnetizing mmf, interpoles, characteristics, parallel operation.

Rosenberg generator.

Unit-3

DC Motors:

Principle, back emf, types, production of torque, armature reaction & interpoles,

characteristics of shunt, series & compound motor, DC motor starting. Speed Control of DC

Motor:

Armature voltage and field current control methods, Ward Leonard method. Braking,

losses and efficiency, direct & indirect test, Swinburne’s test, Hopkinsion test, field &

retardation test, single-phase series motor.

Unit-4

Transformers:

Construction, types, emf equation. No load and load conditions. Equivalent

circuits, Vector diagrams, OC and SC tests, Sumpner’s back-to-back test, efficiency. voltage

regulation, effect of frequency, parallel operation, autotransformers, switching currents in

transformers, separation of losses.

Unit-5

Polyphase Transformers:

Single unit or bank of single-phase units, polyphase connections,

Open delta and V connections, Phase conversion: 3 to 6 phase and 3 to 2 phase conversions,

Effect of 3-phase winding connections on harmonics, 3-phase winding transformers, tertiary