THREE PHASE INDUCTION MOTORS QUIZ

3-phase wound rotor morors are also called _____ motors.

Synchronous

Slip ring

Commutator

Series

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YOUR ANSWER : ?

The direction of rotation of field in a 3 phase induction motor depends upon _____

Magnitude of supply voltage

Phase sequence of supply voltage

Supply frequency

Number of poles

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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

50 Hz

None of the listed here

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The maximum torque in an induction motor depends on

All of the listed here

Rotor inductive reactance

Frequency

Square of supply voltage

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As load on an induction motor goes on increasing

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

Its power factor remains constant

Its power factor goes on increasing even after full load

Its power factor goes on decreasing

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In an induction motor, no load the slip is generally

1.5 %

2%

4%

Less than 1%

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If the rotor slots are made deeper, rotor resistance is ______

Increased under running conditions

None of the listed here

Increased at starting

Decreased at starting

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The complete circle diagram of induction motor can be drawn with the help of data found from

Blocked rotor test

All of these

Stator resistance test

No-load test

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A 3 phase induction motor is ________

Very costly

A variable speed motor

Not easily maintainable

Essentially a constant speed motor

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

Unity

0.2 lagging

0.2 leading

0.5 leading

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YOUR ANSWER : ?

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