THREE PHASE INDUCTION MOTORS QUIZ

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

Greater than

Smaller than

None of the listed here

Equal to

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

Bearings

None of these

Stator core

Shaft

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As load on an induction motor goes on increasing

Its power factor remains constant

Its power factor goes on increasing even after full load

Its power factor goes on decreasing

Its power factor goes on increasing up to full load and then it falls again

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

(1-S) × rotor input

S × rotor input

None of the listed here

(1+S) × rotor input

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An induction motor is

Self starting with high torque

Self starting with zero torque

Non self starting

Self starting with low torque

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The shaft of induction motor is made of

Any of the listed here

Hollow

Flexible

Stiff

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An induction motor is so called because its operation depends on

Hysteresis

Eddy currents

Self induction

Mutual induction

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The condition of induction motor at stand still resemble those of a transformer whose secondady is _______

Short circuited

Open circuited

Supplying a variable resistive load

None of the listed here

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The good power factor of an induction motor can be achieved if the average flux density in the air gap is

Large

Small

Infinity

Absent

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

25 Hz

60 Hz

None of the listed here

50 Hz

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YOUR ANSWER : ?

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