I

DC Machines: Constructional features – principle of operation of DC generator – armature winding - types - e.m.f. equation - armature reaction – effects of armature reaction - demagnetizing and cross magnetizing ampere- turns - compensating winding - commutation – methods to improve commutation – e.m.f. in coil undergoing commutation – reactance e.m.f.- effect of brush shift- inter poles.

II

DC Generator: Types of excitation – separately excited- self excited shunt, series and compound machines – the magnetization curve – condition for self excitation- field critical resistance- critical speed- load characteristics of generators – load critical resistance – voltage regulation - parallel operation of shunt, series and compound generators – power flow diagram- losses and efficiency- condition for maximum efficiency- applications.

III

DC Motors: principle of operation of DC motor – developed torque – performance characteristics and operating characteristics of shunt, series and compound motors. Starting – three point and four point starters – design of starter resistance for shunt motor - methods of speed control of shunt , series and compound motors – solid state speed control (block diagram) – power flow diagram- losses and efficiency Testing of D C machines – Swinburne’s test - Hopkinson’s test - Field’s test – retardation test- applications

IV

Single Phase transformers: Principle of operation - constructional details - e.m.f equation - operation on no load - magnetizing current wave form - load operation - phasor diagram - equivalent circuit – per unit impedance - losses and efficiency - condition for maximum efficiency – voltage regulation- approximate expression for voltage regulation- harmonics in single phase transformers - OC and SC tests - Sumpner’s tests - parallel operation – applications.

V

Three phase transformers: Constructional details- choice of transformer connections- Scott connection (three phase to two phase only) - oscillating neutral- tertiary winding – vector groups- equivalent circuits- tap changing transformers- no load tap changing – on load tap changing- cooling of transformers.

Distribution transformers- all day efficiency- auto transformers- saving of copper applications.