OBJECTIVE : To know the construction, principle of operation and characteristics of d.c. machines and transformers.
Principle of energy conversion - coupling field reaction - Energy storage in singly and multiply excited systems - stored energy and mechanical force - concept of coenergy and the force equation - Faraday's law of electromagnetic induction and Ampere's law of force - electromechanical transducers - rotating machines.
Constructional features of d.c.machines - EMF equation - armature winding fundamentals - characteristics of different types of d.c. generators - commutation and armature reaction. D.C. motors - torque equation - characteristics - starters - speed control.
Swinburne's test - Hopkinson's test - retardation test - load test - electric braking - parallel operation of d.c. generators.
Principle of operation, types and constructional features of single phase and three phase transformers - phasor diagram - equivalent circuit - regulation and efficiency- core loss reduction.
Three phase transformer connection - Scott connection - auto transformer - all day efficiency - Sumpner's test - parallel operation of transformers - no load and on-load tap changing transformers - in-rush phenomenon and its prevention.
