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By Prof. L.Umanand, Principal Research Scientist, Power Electronics Group, CEDT, IISC Bangalore
ELECTRICAL MACHINES - III SYLLABUS :
This subject is an extension of previous machines courses. It deals with the detailed analysis of
Synchronous generators and motors which are the prime source of electrical power generation and its
utilities. Also concerns about the different types of single phase motors which are having significant
applications in house hold appliances and control systems.
UNIT – I
Construction and Principle of operation
Constructional Features of round rotor and salient pole machines – Armature windings – Integral slot and
fractional slot windings; Distributed and concentrated windings – distribution, pitch and winding factors –
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
UNIT – III
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.
UNIT – IV
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 wave
form – determination of sub-transient, transient and steady state reactances.
UNIT – V
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 .
Excitation and power circles – hunting and its suppression – Methods of starting – synchronous induction
UNIT – VII
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.
UNIT – VIII
Principle & performance of A.C. Series motor-Universal motor – Principle of permanent magnet and
1. Electric Machines – by I.J.Nagrath & D.P.Kothari, Tata Mc Graw-Hill Publishers, 7th Edition 2005.
2. Electrical Machines – by P.S. Bimbra, Khanna Publishers.
1. The Performance and Design of A.C.Machines – by M.G.Say, ELBS and Ptiman & Sons.
2. Electric Machinery – by A.E. Fitzgerald, C.Kingsley and S.Umans, Mc Graw-Hill Companies, 5th
3. Theory of Alternating Current Machinery by Langsdorf, Tata Mc Graw-Hill, 2nd edition.
4. Electromachanics-III (Synchronous and single phase machines), S.Kamakashiah, Right