Electrical Machines and Applications — Summer 2023

Explain the significance of back EMF in DC motor.

Derive EMF equation of single-phase transformer.

Explain the theory of production of rotating magnetic field with three-phase supply in induction motor.

Explain open-circuit test of single-phase transformer.

List the conditions for parallel operation of single-phase transformers.

Explain auto-transformer. Derive the equation for the saving in copper. List the applications of auto-transformer.

Explain Scott connection of transformers with necessary diagrams.

List advantages and disadvantages of poly-phase induction motor.

Derive the condition for maximum torque under running condition for induction motor. Also derive the equation for maximum torque.

Explain double field revolving theory of single-phase induction motor.

Define slip. Derive the equation of speed of rotor field in space.

Explain primary resistor starter for three-phase induction motor.

Write technical note on: Shaded-pole single-phase induction motor.

Define pole pitch, coil pitch and commutator pitch.

Derive the EMF equation of DC generator.

Explain the necessity of starter in DC Motor and Explain three-point starter with necessary diagram.

Draw only torque v/s current, speed v/s current and speed v/s torque characteristics of DC shunt motor.

Derive the equation of armature torque for DC motor.

Explain the theory of armature reaction in DC generator.

List the advantages of having stationary armature and rotating field system.

Explain the working of DC servo motor with necessary diagram.

Explain the effect of increased load on synchronous motor with constant excitation with the help of vector diagram.

Define Distribution factor, Coil-span factor and voltage regulation.

Explain the working of stepper motor with necessary diagram.

Explain zero power factor method for finding voltage regulation of an alternator.