MCQ or quiz on dc motor
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DC Motors MCQ Or Quiz, Electrical Objective Questions

Posted on by Chetan Shidling

Hello guys, welcome back to my blog. In this article, I will discuss dc motor MCQ or quiz, quiz questions for dc motors, or electrical interview questions related to dc motors.

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Also read – Electrical Machines Questions And Answers.

DC Motors MCQ Or Quiz

01. By seeing which part of the motor we can say this is the dc motor?

  1. Frame
  2. Shaft
  3. Commutator
  4. Stator

Ans: c

02. The application in which D.C. series motor is invariably tried?

  1. Starter for a car
  2. Drive for a water pump
  3. Fan motor
  4. Motor operation in A.C. or D.C.

Ans: a

03. Why fractional pitch winding is used in dc motor?

  1. to improve cooling
  2. to reduce copper losses
  3. to increase the generated e.m.f.
  4. to reduce the sparking

Ans: d

04. The three-point starter is most suitable for?

  1. shunt motors
  2. compound motors as well as shunt
  3. the compound, shunt,  and series motors
  4. all D.C. motors

Ans: b

05. If the maximum power for a D.C. motor is established, then the efficiency of the dc motor will be?

  1. 100%
  2. around 90%
  3. anywhere between 75% and 90%
  4. less than 50%

Ans: d

06. The ratio of starting torque to full-load torque is less in which motor?

  1. series motors
  2. shunt motors
  3. compound motors
  4. none of the above

Ans: b

07. In the dc motor which part will sustain the maximum temperature increase?

  1. Slip rings
  2. Commutator
  3. Field winding
  4. Armature winding

Ans: c

08. The direction of the dc motor is determined by which law?

  1. Lenz’s law
  2. Faraday’s law
  3. Columb’s law
  4. Fleming’s left-hand rule

Ans: d

09. Which of the following needs high starting torque?

  1. Blowers
  2. Conveyors
  3. Air compressors
  4. Centrifugal pumps

Ans: b

10. In the Dc motor, the starting resistance is?

  1. low
  2. around 500 Q
  3. 1000 Q
  4. infinitely large

Ans: a

11. In dc series motor, the speed is?

  1. directly proportional to the armature current
  2. directly proportional to the square of the armature current
  3. directly proportional to the field current
  4. inversely proportional to the current of armature

Ans: d

12. If the armature current is reduced to 50% the torque of the motor will be?

  1. 100% of the previous value
  2. 50% of the previous value
  3. 25% of the previous value
  4. 10% of the previous value
  5. none of the above

Ans: c

13. In the dc motor, the current drawn by the armature of the motor is directly proportional to?

  1. the torque required
  2. the speed of the motor
  3. the voltage across the terminals
  4. none of the above

Ans: a

14. In dc motor, the power mention on the nameplate indicates?

  1. the power is drawn in kW
  2. the power is drawn in kVA
  3. the gross power
  4. the output power at the shaft

Ans: d

15. The motor which has got maximum self-loading property is?

  1. Series motor
  2. Shunt motor
  3. Cumulatively compounded ‘motor
  4. Differentially compounded motor

Ans: d

16. The series motor is used?

  1. where the constant load is required
  2. where frequently load changes
  3. where operating speed is needed constant
  4. none of the above

Ans: d

17. For the same full load speed and H.P. rating, the following motor which has poor starting torque?

  1. shunt
  2. series
  3. differentially compounded
  4. cumulatively compounded

Ans: c

18. The compensating winding is provided in a dc series motor is?

  1. which as the separately wound unit
  2. in parallel  to the armature winding
  3. in series to the armature winding
  4. in parallel to the field winding

Ans: c

19. In the dc motor, the sparking at commutator results?

  1. damage to commutator segments
  2. damage to commutator insulation
  3. increased power consumption
  4. all of the above

Ans: d

20. If the supply voltage is increased in the dc motor, which of the following will decrease?

  1. Starting torque
  2. Operating speed
  3. Full-load current
  4. All of the above

Ans: c

Tags: DC Motors MCQ Or Quiz, Electrical Objective Questions.

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Chetan Shidling

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