Electrical Machines -3

Construction and Principle of operation : Constructional features of round rotor and salient pole machines - Armature winding - Integral slot and fractional slot windings; Distributed and concentrated windings - Distribution, pitch and winding factors - E.M.F. Equation. Synchronous Generator Characteristics : Harmonics in generated e.m.f. - Suppression of harmonics - Armature reaction - Leakage reactance - Synchronous reactance and impedance - Experimental determination - Phasor diagram - Load characteristics. Regulation of Synchronous Generator : Regulation by synchronous impedance method, M.M.F. method, Z.P.F. method and A.S.A. methods - Salient pole alternators - Two reaction analysis - experimental determination of Xd and Xq (Slip test) Phasor diagrams - Regulation of salient pole alternators. Parallel Operation of Synchronous Generator : Synchronizing alternators with infinite bus bars - Synchronizing power torque - Parallel operation and load sharing - Effect of change of excitation and mechanical power input. Analysis of short circuit current waveform - Determination of sub-transient, transient and steady state reactances. Synchronous Motors - Principle of Operation : Theory of operation - Phasor diagram - Variation of current and power factor with excitation - Synchronous condenser - Mathematical analysis for power developed. Power Circles : Excitation and power circles - Hunting and its suppression - Methods of starting - Synchronous induction motor. Single Phase Motors : Single phase motors : Single phase induction motor - Constructional features - Double revolving field theory - Elementary idea of cross-field theory - Split phase motors - Shaded pole motor. Special Motors : Principle and performance of A.C. series motor - Universal motor - Principle of permanent magnet and reluctance motors.