Electrical Machines I1. Unit-1
2. Unit-2
3. Unit-3
4. Unit-4
5. Unit-5
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Electrical Machines I SyllabusUNIT – I
Review of transformer theory, Auto-transformer equivalent circuit and phasor diagram, three-phase transformers, core and shell type transformer, three-phase tank, three-phase unit, different connections and vector groups, three winding transformer connections, parameters of three winding transformer, coupled circuit view point. UNIT – II Parallel operation of single-phase and three-phase transformer, Scott connection, opendelta, back-to-back test, separation of losses, excitation phenomenon in transformers. UNIT – III Electromagnetic principle of DC machine, constructional details, production of voltage and torque, BLV and BLI concepts, classification of DC machine, conditions of self excitation, armature reaction and its effect, flux and mmf waves, effect of brush shift, commutation, methods of improving commutation, Operating characteristics of DC generator, parallel operation. UNIT – IV DC machine as motor, armature reaction, its effect on motor working, electrical and mechanical characteristics of DC motor, starting and speed control of DC motors, losses in DC machines, Testing of DC machines, Swinburne’s test, regenerative and retardation test. UNIT – V Cross-field machines, armature winding, transformer cooling, wide band transformer, pulse transformer, audio frequency transformer. |