T4Tutorials .PK

FAULTS, THEIR CAUSES AND REMEDIES OF A.C. 3 PHASE MOTOR MCQs – CHAPTER 3 DAE

1. Number of slip rings in squirrel cage motor is:

(A) Zero


(B) 3


(C) 2


(D) 4




2. Starting torque of squirrel cage induction motor is:

(A) Very high


(B) Low


(C) Zero


(D) High




3. Resistance of the stator of 3-phase motor should not be less than:

(A) 1000 Ohm


(B) 1 M Ohm


(C) 10k Ohm


(D) 2 M Ohm




4. A 3-phase wound motor does not run; its cause may be:

(A) Open circuit in field


(B) Loose bearing


(C) Low load


(D) None of these




5. Which of the following is a mechanical fault in 3-phase synchronous motor:

(A) Punctured the insulation


(B) Breaking the motor fan


(C) Burning slip rings


(D) Open circuit




6. Wound rotor motor can be run on:

(A) None of these


(B) D.C supply only


(C) Both A.C & D.C


(D) A.C supply only




7. Stator of 3-phase synchronous motor is too hot; possible causes:

(A) Overload


(B) Both a & b


(C) Low excitation


(D) None of these




8. If wrong connection for a given voltage, then motor will be:

(A) Overheated


(B) Noise on no load


(C) Both a & b


(D) None of these




9. Wound rotor motor runs at half speed; possible causes:

(A) Short circuit


(B) No load


(C) Open circuit in rotor connection


(D) Earth fault




10. Failure of bearing is:

(A) Mechanical fault


(B) Magnetic fault


(C) Earth fault


(D) Electrical fault




Exit mobile version