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Single Phase Induction Motors

Study 110 Electrical Engineering MCQs with correct answers and explanations.

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11Electrical EngineeringMedium

In a A.C. series motor armature coils are usually connected to commutator________?

Asolidly

Bthrough capacitors

Cthrough resistance

Dthrough reactances

Correct answer

C. through resistance

Explanation

The correct answer is through resistance.

12Electrical EngineeringMedium

Which of the following single-phase motors is suitable for timing and control purposes?

AUniversal motor

BRepulsion motor

CReluctance motor

DSeries motor

Correct answer

C. Reluctance motor

Explanation

The correct answer is Reluctance motor.

13Electrical EngineeringMedium

The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be________?

Aat the end connections

Bat the end terminals

Cat the slot edge where coil enters or comes out of the slot

Danywhere on the winding inside a slot

Correct answer

C. at the slot edge where coil enters or comes out of the slot

Explanation

The correct answer is at the slot edge where coil enters or comes out of the slot.

14Electrical EngineeringMedium

Speed torque characteristic of a repulsion induction motor is similar to that of a D.C________?

Acompound motor

Bseries motor

Cshunt motor

Dseparately excited motor

Correct answer

A. compound motor

Explanation

The correct answer is compound motor.

15Electrical EngineeringMedium

The power factor of a single-phase induction motor is usually?

Aunity to 0.8 leading

Balways leading

Cunity

Dlagging

Correct answer

D. lagging

Explanation

The correct answer is lagging.

16Electrical EngineeringMedium

The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it________?

Ahelps the rotor teeth to remain under the stator teeth

Bimproves the power factor

Cimproves the efficiency

Dhelps in reducing the tendency of the rotor teeth to remain under the stator teeth

Correct answer

D. helps in reducing the tendency of the rotor teeth to remain under the stator teeth

Explanation

The correct answer is helps in reducing the tendency of the rotor teeth to remain under the stator teeth.

17Electrical EngineeringMedium

If a particular application needs high speed and high starting torque, then which of the following motor will be preferred?

AUniversal motor

BCapacitor start and run motor

CShaded pole type motor

DCapacitor start motor

Correct answer

A. Universal motor

Explanation

The correct answer is Universal motor.

18Electrical EngineeringMedium

Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a________?

Anone of the above

Bmagnetic relay

Ccentrifugal switch

Dthermal relay

Correct answer

B. magnetic relay

Explanation

The correct answer is magnetic relay.

19Electrical EngineeringMedium

Torque developed by a single phase induction motor at starting is________?

Anone of the above

Bpulsating

Cuniform

Dnil

Correct answer

D. nil

Explanation

The correct answer is nil.

20Electrical EngineeringMedium

The rotor of a hysteresis motor is made of________?

Achrome steel

Bcast iron

Ccopper

Daluminium

Correct answer

A. chrome steel

Explanation

The correct answer is chrome steel.

The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be________?

Aat the end connections

Bat the end terminals

Cat the slot edge where coil enters or comes out of the slot

Danywhere on the winding inside a slot

Correct answer

C. at the slot edge where coil enters or comes out of the slot

Explanation

The correct answer is at the slot edge where coil enters or comes out of the slot.

The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it________?

Ahelps the rotor teeth to remain under the stator teeth

Bimproves the power factor

Cimproves the efficiency

Dhelps in reducing the tendency of the rotor teeth to remain under the stator teeth

Correct answer

D. helps in reducing the tendency of the rotor teeth to remain under the stator teeth

Explanation

The correct answer is helps in reducing the tendency of the rotor teeth to remain under the stator teeth.