POWER PLANT ENGINEERING QUIZ

In a 3 phase induction motor, the rotor speed is _____ the synchronous speed.

Greater than

None of the listed here

Smaller than

Equal to

TRUE ANSWER : ?
YOUR ANSWER : ?

The shaft of induction motor is made of

Any of the listed here

Stiff

Flexible

Hollow

TRUE ANSWER : ?
YOUR ANSWER : ?

The low power factor of induction motor is due to

The reactive lagging magnetizing current necessary to generate the magnetic flux

All of these

Rotor leakage reactance

Stator reactance

TRUE ANSWER : ?
YOUR ANSWER : ?

In a squirrel cage rotor, the bars are not placed parallel to the shaft but are skewed to have ______

Less rotor losses

None of the listed here

Greater mechanical strength

Uniform torque

TRUE ANSWER : ?
YOUR ANSWER : ?

When the rotor of a 3-phase induction motor is blocked, the slip is _____

1

0

0.5

0.1

TRUE ANSWER : ?
YOUR ANSWER : ?

Friction and windage loss of a 3 phase induction motor are

Maximum at no load

None of the listed here

Remains the same at all loads

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 _____

300 rpm

1000 rpm

1200 rpm

600 rpm

TRUE ANSWER : ?
YOUR ANSWER : ?

If a 3-phase induction motor is running at slip S, then rotor copper loss is equal to

(1-S) × rotor input

None of the listed here

S × rotor input

(1+S) × rotor input

TRUE ANSWER : ?
YOUR ANSWER : ?

A 3 phase induction motor is running at 2% slip. If the input to rotor is 1000 W, then mechanical power developed by the motor is _______

20 W

500 W

980 W

200 W

TRUE ANSWER : ?
YOUR ANSWER : ?

The rotor winding of a 3phase wound rotor induction motor is generally _______ connected.

Partly star and partly delta

Delta

Star

None of the listed here

TRUE ANSWER : ?
YOUR ANSWER : ?

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