THREE PHASE INDUCTION MOTORS QUIZ

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

980 W

500 W

200 W

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The 3- phase induction motor is so designed that the rotor should have ______ under running conditions.

Large slip

high resistance

Low resistance

High reactance

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An induction motor with 1000 r.p.m. speed will have

2 poles

8 poles

4 poles

6 poles

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

2400 rpm

1600 rpm

400 rpm

1200 rpm

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5 H.P., 50Hz, 3-phase, 440 V, induction motors are available for the following r.p.m. Which motor will be the costliest?

1440 rpm

1000 rpm

2880 rpm

730 rpm

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In a squirrel cage induction motor, the number of rotor bars is generally ________

Even number

Equal to stator poles

Prime number

None of the listed here

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The synchronous speed of a 3-phase induction motor having 20 poles and connected to a 50 Hz source is _____

600 rpm

1000 rpm

1200 rpm

300 rpm

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

Magnitude of supply voltage

Number of poles

Phase sequence of supply voltage

Supply frequency

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At starting of a double squirrel cage induction motor _______

Lower winding is more effective

Lower cage winding has low reactance

Outer cage winding has good pf

None of the listed here

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Reduced voltage starter can be used with

Squirrel cage as well as slip ring induction motor

None of these

Squirrel cage induction motor only but not with slip ring motor

Slip ring motor only but not with squirrel cage induction motor

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