Synchronous & Induction Machines (PCEET402) Syllabus

Principle of operation of 3-phase alternators, classification, constructional features, types of armature windings, winding diagram of a 3-phase, 12-slot, 2-pole, single layer full-pitched armature winding (not for evaluation), coil-span factor and distribution factor (sinusoidal flux distribution only), EMF equation, numerical problems. Cylindrical-rotor type synchronous generator on no-load — open circuit characteristics; on load — armature reaction, effect of armature reaction, synchronous impedance, equivalent circuit, phasor diagram, numerical problems. Voltage regulation — OC and SC tests, EMF and MMF methods, ZPF test, Potier method, numerical problems.

Power flow equations in cylindrical-rotor type synchronous generator, numerical problems. Parallel operation — synchronous generator on infinite bus-bar, conditions, methods of synchronisation, effect of change of mechanical input, effect of change of excitation, V-curves and inverted V-curves, numerical problems. Salient-pole synchronous generator — two reaction theory, phasor diagram, slip test for determination of Xd and Xq, numerical problems. Synchronous motor — rotating magnetic field, principle of operation, starting methods. Power developed (cylindrical rotor and salient-pole type) — excitation power and reluctance power, power angle characteristics, losses and efficiency, numerical problems. V-curves and inverted V-curves.

3-phase induction motor — principle of operation, classification, constructional features, torque equation, torque-slip characteristics, relation between starting torque, maximum torque and full-load torque, numerical problems. Phasor diagram, equivalent circuit. Power flow diagram — losses and efficiency, numerical problems. No-load and blocked-rotor tests, circle diagram, numerical problems. Starting of induction motors — types of starters (DOL, autotransformer, star-delta, rotor resistance starter — no design). Braking of induction motors — plugging, dynamic braking, regenerative braking (concepts only). Speed control — stator voltage control, V/f control, rotor resistance control.

Induction generator — line excited and self-excited induction generators (principle of operation only), torque-slip characteristics for braking, motoring and regeneration. Single-phase induction motors — double revolving field theory, equivalent circuit, torque-slip characteristics. Types of 1-phase induction motors — split-phase, capacitor-start induction-run, permanent capacitor types, applications.