THREE PHASE INDUCTION MOTORS QUIZ

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

Leakage reactances are increased

No load current is decreased

Leakage reactances are decreased

None of the listed here

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YOUR ANSWER : ?

The shaft of an induction motor is made of

Cast iron

High speed steel

Stainless steel

Carbon steel

TRUE ANSWER : ?
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The shaft of induction motor is made of

Hollow

Stiff

Any of the listed here

Flexible

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At no load the rotor core loss of a 3 phase induction motor is

Small

Practically zero

Large

None of the listed here

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YOUR ANSWER : ?

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

0.1

0.5

1

0

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In an induction motor, no load the slip is generally

1.5 %

2%

Less than 1%

4%

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Slip of an induction motor is negative when

Rotor speed is less than the synchronous speed of the field and are in the same direction

None of these

Rotor speed is more than the synchronous speed of the field and are in the same direction

Magnetic field and rotor rotate in opposite direction

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 becomes zero

Rotor current remains same

Decreases the rotor current

TRUE ANSWER : ?
YOUR ANSWER : ?

One of the speeds of a 2 speed squirrel cage induction motor is 800 rpm. The other speed will be _____

2400 rpm

400 rpm

1200 rpm

1600 rpm

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If an induction motor is running at slip S, then rotor output is ______

(1+S) × rotor input

(1-S) × rotor input

S × rotor input

(S-1) × rotor input

TRUE ANSWER : ?
YOUR ANSWER : ?