ELE – 402 ENERGY CONVERSION - I

D.C.Machines: Constructional features, Magnetic circuits, Armature winding simple lap and wave winding, EMF equation, Electromagnetic torque in terms of air gap density and in terms of induced emf. Armature reaction - Spatial distribution of main pole field, armature field and resultant field. Commutation, Methods of improving commutation, commutating pole winding, compensating winding.

D.C.Generator: Methods of excitation, open circuit characteristics, condition for building up of voltage in shunt generators, critical resistance, Load characteristics of separately and self excited generators, various voltage drops, voltage regulation.

D.C. Motor: Operating characteristics of motors, regions of normal operation, Matching of speed torque characteristics of motors and load, applications. Starting of shunt and series motors. Speed control - motor speed in terms of applied voltage and air gap flux, Field control - advantages and disadvantages, Armature control - advantages and disadvantages, ward - Leonard speed control. Losses and efficiency, copper loss, Brush contact loss, iron loss, Mechanical losses, efficiency at various outputs. Testing - Hopkinsons test.

Single-phase Transformer: Arrangement of core and winding in core and shell type transformers. Principles of operation, voltage ratio. Operation no-load, No-load or exciting current and its components, exciting impedance and admittance, phasor diagram. Operation with Load, Primary and secondary current, current relation, Leakage fluxes, various constants - percent values, performance equation, equivalent circuit, Approximate equivalent circuit, phasor diagram, voltage regulation, Losses and efficiency, condition for maximum efficiency, all day efficiency, testing - polarity test, open circuit and short circuit tests, back to back test. Parallel operation of single phase transformer, load sharing.

Auto transformer: Principles of operation, voltage, current and power relationships, phasor diagrams, equivalent circuit, comparison with two-winding transformer.

Three Phase transformer: Types of core construction, Arrangements of windings, Transformer connections - operating characteristics of star-star, star-delta and delta-star connection. Open delta and zigzag connection. Phase transformation-three phase to two phase, three phase to six phase, three phase to twelve phase transformation, application.

Three winding Transformer: Arrangements of windings, various constants, the star equivalent circuit, applications.

TEXTBOOKS:

1. The performance and design of D.C. machine - A.E.Clayton

2. Theory of A.C. machines - A.S. Langsdorf

3. A.C.Machines - M.G.Say

4. Electric Machinery- A.E.Fitzgerald, S.K.Kindsley and A. Kurko

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