ELECTRICAL MACHINES QUIZ

The compensating winding in a DC machine

is located on pole shoes for avoiding the flashover at the commutator.

is located in armature slots for compensation of the armature reaction.

is located on commutating poles for improving commutation.

is located on pole shoes to avoid the sparking at the brushes.

TRUE ANSWER : ?
YOUR ANSWER : ?

Hunting in a synchronous cannot be due to

windage friction.

variable frequency.

variable load.

variable supply voltage.

TRUE ANSWER : ?
YOUR ANSWER : ?

Transformers operating in parallel will share the load depending upon their

percentage impedance.

leakage reactance.

efficiency.

rating.

TRUE ANSWER : ?
YOUR ANSWER : ?

For a fault at the terminal of a synchronous generator, the fault current is maximum for a

3 - phase to ground fault.

line to line fault.

3 - phase fault.

line to ground fault.

TRUE ANSWER : ?
YOUR ANSWER : ?

Two identical loss less series motors connected in series across a dc supply voltage, runs at speed of N1 and N2, then ratio of their output power is

N1 : N2.

none.

N12 : N22.

1 : 1.

TRUE ANSWER : ?
YOUR ANSWER : ?

Capacitor in split phase induction motor is used to

improve the starting torque.

reduce the harmonics.

start the motor.

improve the power factor.

TRUE ANSWER : ?
YOUR ANSWER : ?

The speed of stator rotating magnetic field (RMF) with respect to rotor is

S.Ns

Nr

Zero

Ns

TRUE ANSWER : ?
YOUR ANSWER : ?

Dynamic braking is very effective for

shunt motors.

series motors.

separately excited motors.

differential compound motors.

TRUE ANSWER : ?
YOUR ANSWER : ?

A shunt generator is running at 1000 rpm. If flux is reduced by half, then what is the new speed?

0.

1000.

500.

2000.

TRUE ANSWER : ?
YOUR ANSWER : ?

For a standard frequency the machine operates at a particular speed known as

normal speed.

any of the above.

slip speed.

synchronous speed.

TRUE ANSWER : ?
YOUR ANSWER : ?

↑