Polyphase Induction Motors - Interview Questions | Exam2Win

Take a timed mock test specifically for Polyphase Induction Motors.

26. Rotor rheostat control method of speed control is used for

A. squirrel-cage induction motors only

B. slip ring induction motors only

C. both (a) and (b)

D. none of the above

Explanation:

27. A 3-phase induction motor delta connected is carrying too heavy load and one of its fuses blows out. Then the motor

A. will continue running burning its one phase

B. will continue running burning its two phase

C. will stop and carry heavy current causing permanent damage to its winding

D. will continue running without any harm to the winding

Explanation:

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

A. 0.2 lagging

B. 0.2 leading

C. 0.5 leading

D. unity

Explanation:

29. If an induction motor with certain ratio of rotor to stator slots, runs at 1/7 of the normal speed, the phenomenon will be termed as

A. humming

B. hunting

C. crawling

D. cogging

Explanation:

30. The speed of a squirrel-cage induction motor can be controlled by all of the following except

A. changing supply frequency

B. changing number of poles

C. changing winding resistance

D. reducing supply voltage

Explanation:

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