D.c. Machines and Synchronous Machines

D.C. Generator Classification of D.C. generator, Types of armature winding, E.M.F. equation, Armature reaction, Commutation, No load and load characteristics, Use of interpoles & compensating winding (only qualitative treatment). D.C. Motors Classification, Back E.M.F. equation, Torque equation, Characteristics of shunt, series & compound motors, Speed control of shunt and series compound motors, Losses in D.C. machines both generator and motor. Losses and efficiency, Direct and indirect methods of testing of D.C. machines, Permanent magnet D.C. motors and brushless D.C. motors, Applications of D.C. motors, Power flow diagram (all tests to be discussed). Synchronous machines Basic principle of operation, Construction of salient and non-salient pole synchronous machines, Generated E.M.F., Effect of distribution of winding and use of chorded coils. Voltage regulation by EMF, MMF, ZPF & ASA method Synchronizing to infinite bus bars, Parallel operation of alternators. Operating characteristics, Power angle characteristics, Excluding armature resistance, Operating for fixed input and variable excitation and vice versa for both generating and motoring mode, V curves of synchronous machines, Power flow equations including armature resistance, Capability curves of synchronous generators, Hunting in synchronous machines, Damper winding, Starting methods for hunting in synchronous machines. Salient pole synchronous machines, Two-reaction theory, Power angle diagram, Reluctance power, Slip test.