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MCQs 1: In a D.C. shunt motor, speed is______________?

independent of armature current directly proportional to the armature current proportional to the square of the current inversely proportional to the armature current
Answer Explanation

MCQs 2: A direct on line starter is used: for starting motors___________?

up to 5 H.P up to 10 H.P up to 15 H.P up to 20 H.P
Answer Explanation

MCQs 3: What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?

The motor will stop The motor will continue to run The armature may burn The motor will run noisy
Answer Explanation

MCQs 4: In case of D.C. shunt motors the speed is dependent on back e.m.f. only because____________?

back e.m.f. is equal to armature drop armature drop is negligible flux is proportional to armature current flux is practically constant in D:C. shunt motors
Answer Explanation

MCQs 5: In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be_____________?

almost negligible rated full-load current less than full-load current more than full-load current
Answer Explanation

MCQs 6: These days D.C. motors are widely used in____________?

pumping sets air compressors electric traction machine shops
Answer Explanation

MCQs 7: By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?

Frame Shaft Commutator Stator
Answer Explanation

MCQs 8: In which of the following applications D.C. series motor is invariably tried?

Starter for a car Drive for a water pump Fan motor Motor operation in A.C. or D.C
Answer Explanation

MCQs 9: In D.C. machines fractional pitch winding is used__________?

to improve cooling to reduce copper losses to increase the generated e.m.f. to reduce the sparking
Answer Explanation

MCQs 10: A three point starter is considered suitable for______________?

shunt motors shunt as well as compound motors shunt, compound and series motors all D.C. motors
Answer Explanation

MCQs 11: In case-the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be______________?

100% around 90% anywhere between 75% and 90% less than 50%
Answer Explanation

MCQs 12: The ratio of starting torque to full-load torque is least in case of____________?

series motors shunt motors compound motors none of the above
Answer Explanation

MCQs 13: In D.C. motor which of the following can sustain the maximum temperature rise?

Slip rings Commutator Field winding Armature winding
Answer Explanation

MCQs 14: Which of the following law/rule can he used to determine the direction of rotation of D.C. motor ?

Lenz’s law Faraday’s law Coloumb’s law Fleming’s left-hand rule
Answer Explanation

MCQs 15: Which of the following load normally needs starting torque more than the rated torque?

Blowers Conveyors Air compressors Centrifugal pumps
Answer Explanation

MCQs 16: The starting resistance of a D.C. motor is generally_______________?

low around 500 Q 1000 Q infinitely large
Answer Explanation

MCQs 17: The speed of a D.C. series motor is_____________?

proportional to the armature current proportional to the square of the armature current proportional to field current inversely proportional to the armature current
Answer Explanation

MCQs 18: In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to

100% of the previous value 50% of the previous value 25% of the previous value 10% of the previous value none of the above
Answer Explanation

MCQs 19: The current drawn by the armature of D.C. motor is directly proportional to__________?

the torque required the speed of the motor the voltage across the terminals none of the above
Answer Explanation

MCQs 20: The power mentioned on the name plate of an electric motor indicates____________?

the power drawn in kW the power drawn in kVA the gross power the output power available at the shaft
Answer Explanation

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