Electrical-Machines-III Free Download


About Book

Single Phase Transformers – Construction and Operation Single phase transformers – Types – Constructional details – Minimization of hystersis and eddy current losses – e.m.f. equation – Operation on no load and on load – Phasor diagrams. Single Phase Transformers – Performance Equivalent circuit – Losses and efficiency – Regulation. All day efficiency – Effect of variations of frequency and supply voltage on iron losses. Testing of Single Phase Transformer and Autotransformer OC and SC tests -Sumpner’s test – Predetermination of efficiency and regulation – Separation of losses test – Parallel operation with equal and unequal voltage ratios – Autotransformers – Equivalent circuit – Comparison with two winding transformers. Polyphase Transformers Polyphase transformers – Polyphase connections – Y/Y, Y/D, D/Y, D/Dand open D , Third harmonics in phase voltages – Three winding transformers – Tertiary windings – Determination of Zp, Zs, and Zt transients in switching – Off load and on load tap changing ; Scott connection. Polyphase Induction Motors Polyphase induction motors – Construction details of cage and wound rotor machines – Production of a rotating magnetic field – Principle of operation – Rotor e.m.f. and rotor frequency – Rotor reactance, Rotor current and pf at standstill and during operation. Characteristics of Induction Motors Rotor power input, Rotor copper loss and mechanical power developed and their inter relation – Torque equation – Deduction from torque equation – Expressions for maximum torque and starting torque – Torque slip characteristic – Double cage and deep bar rotors – Equivalent circuit – Phasor diagram – Crawling and cogging.

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