THREE PHASE INDUCTION MOTORS QUIZ

The magnetising current drawn by a 3 phase induction motor is about _______ of full load stator current.

30 to 50%

5%

10 to 15%

15 to 20 %

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In induction motor, percentage slip depends on

Copper losses in motor

Supply frequency

None of these

Supply voltage

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

0

0.5

1

0.1

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The rotor of an induction motor runs at

Any of the above

Above synchronous speed

Below synchronous speed

Synchronous speed

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The starting torque of an induction motor is maximum when rotor resistance per phase is _____ rotor reactance / phase.

Equal to

Four times

Two times

None of the listed here

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

Star

Partly star and partly delta

Delta

None of the listed here

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In medium sized induction motor, the slip is generally around

0.04 %

0.4 %

14%

4 %

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

1

As small as possible

Large

Very large

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

Smaller than

Greater than

None of the listed here

Equal to

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In the circle diagram for induction motor, the diameter of the circle represents

Line voltage

Rotor current

Running torque

Slip

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