Electrical Machines — Winter 2021

Explain working principle and derive the emf equation of single phase transformer.

Explain equipments used in a substation.

.Explain open circuit and short circuit test on single phase transformer.

What is load factor,diversity factor and plant utilization factor?

Explain power factor. How can we improve power factor?

Give difference between self excited and separately excited DC machine.

With help of phasor diagram explain the operation of practical transformer on load.

Explain the losses of transformer. How these losses are reduce?

Explain various types of losses occurring in a d.c.generator.

What is slip in induction motor? Explain torque/slip characteristics of induction motor.

What do you mean of hunting in Synchronous Machine

Explain commutation in DC machine.

Explain steam power station with neat diagram.

Explain the term ‘Back emf’ in respect to d.c.motor.

Give comparison of squirrel cage and wound rotor motors.

Explain synchronization of alternators. Which conditions must be satisfied for proper synchronization of 3-phase alternators?

Write advantages and applications of auto transformer.

Explain power stages of an induction motor.

Write short note on classification of transmission line.

Write different starters used for 3 phase induction motor and explain any one of them.

Explain the Swinburne’s test of a d.c. machine

Explain equivalent circuit of the single phase transformer.

Write a short note on Ferranti effect.

Explain armature reaction of the d.c. machine. Give its remedies also.

Explain three phase four wire and three phase three wire AC system and merits of each.