THREE PHASE INDUCTION MOTORS QUIZ

If the air gap between the rotor and stator of a 3-phase induction motor is increased, then_______

None of the listed here

No load current is decreased

Leakage reactances are decreased

Leakage reactances are increased

TRUE ANSWER : ?
YOUR ANSWER : ?

If a 4 pole induction motor has a synchronous speed of 1500 rpm, then supply frequency is _____

60 Hz

50 Hz

None of the listed here

25 Hz

TRUE ANSWER : ?
YOUR ANSWER : ?

Insertion of resistance in the rotor of an induction motor to develop a given torque

Increases the rotor current

Rotor current remains same

Decreases the rotor current

Rotor current becomes zero

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following component is usually fabricated out of silicon steel?

Bearings

Shaft

Stator core

None of these

TRUE ANSWER : ?
YOUR ANSWER : ?

The maximum torque in an induction motor depends on

All of the listed here

Square of supply voltage

Frequency

Rotor inductive reactance

TRUE ANSWER : ?
YOUR ANSWER : ?

For higher efficiency of 3-phase induction motor, the slip should be

As small as possible

1

Very large

Large

TRUE ANSWER : ?
YOUR ANSWER : ?

Friction and windage loss of a 3 phase induction motor are

Maximum at no load

Remains the same at all loads

None of the listed here

Minimum at no load

TRUE ANSWER : ?
YOUR ANSWER : ?

The synchronous speed of a 3-phase induction motor having 20 poles and connected to a 50 Hz source is _____

600 rpm

1200 rpm

1000 rpm

300 rpm

TRUE ANSWER : ?
YOUR ANSWER : ?

The shaft of induction motor is made of

Any of the listed here

Hollow

Flexible

Stiff

TRUE ANSWER : ?
YOUR ANSWER : ?

The power factor of an induction motor under no load conditions will be closer to

0.5 leading

Unity

0.2 lagging

0.2 leading

TRUE ANSWER : ?
YOUR ANSWER : ?

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