Constructional features of a DC machines – Principles of operation of DC generator – EMF equation –Types – methods of excitation – no load and load characteristics of DC generators –armature reaction and commutation

Principles of operation of DC motor, back EMF – torque equation –Types –characteristics of DC motors – starting methods – speed control

Losses and efficiency – Testing of DC machines- Brake test, Swinburne’s and Hopkinson’s tests – Applications of DC Machines

Principles of operation – constructional features of single phase and three phase transformers – EMF equation – transformer on no load and load – effects of resistance and leakage reactance of the windings – phasor diagram – equivalent circuit – regulation

Losses and efficiency – all day efficiency – testing using design thinking – polarity test – open circuit and short circuit tests – Auto transformer – three phase transformers connections – Tap changing. Applications: Instrument, Isolation, Distribution and Power Transformers