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MCQ on DC Generator

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DC Generator MCQs; Important mcqs on DC generator

1) The yoke of the DC generator is made of

  1. silicon steel
  2. soft iron
  3. aluminium
  4. cast steel
ANSWER
Answer: ( 4 )
EXPLANATION
No answer description required for this question.

2) The armature of a DC generator is made of

  1. silicon steel
  2. soft iron
  3. aluminum
  4. cast steel
ANSWER
Answer: ( 1 )
EXPLANATION
It is desired that armature should provide low reluctance path for the flux. For that reason, it should be made of high permeability material i.e. silicon steel

3) The coupling field between electrical and mechanical system of a DC generator is

  1. electric field
  2. magnetic field
  3. both electric and magnetic field
  4. none of the above
ANSWER
Answer: ( 2 )
EXPLANATION
No answer description required for this question.

4) The actual working part of a DC machine is

  1. field winding
  2. commutator
  3. armature winding
  4. none of the above
ANSWER
Answer: ( 3 )
EXPLANATION
No answer description required for this question.

5) The armature winding of a DC generator is placed on the rotor to ………..

  1. save iron
  2. reduce losses
  3. facilitate commutation
  4. reduce armature reaction
ANSWER
Answer: ( 3 )
EXPLANATION
No answer description required for this question.

6) The yoke of a DC generator carries ………. pole flux

  1. one half of the
  2. twice of the
  3. four times of the
  4. none of the above
ANSWER
Answer: ( 1 )
EXPLANATION
No answer description required for this question.

7) A four pole DC generator has ……….. magnetic circuits

  1. 2
  2. 4
  3. 8
  4. 16
ANSWER
Answer: ( 2 )
EXPLANATION
In a DC machine, the number of magnetic circuits are as many as the number of poles.

8) The DC generator field structure uses

  1. salient pole arrangement
  2. non salient pole arrangement
  3. both 1 and 2
  4. none of the above
ANSWER
Answer: ( 1 )
EXPLANATION
No answer description required for this question.

9) Small DC machines generally have ……. poles

  1. two
  2. four
  3. eight
  4. sixteen
ANSWER
Answer: ( 1 )
EXPLANATION
No answer description required for this question.

10) The DC machine armature is laminated in order to reduce

  1. reluctance
  2. eddy current loss
  3. hysteresis loss
  4. frictional loss
ANSWER
Answer: ( 2 )
EXPLANATION
No answer description required for this question.

11) The armature conductor current of a DC machine is

  1. AC
  2. DC
  3. pulsating DC
  4. pulsating AC
ANSWER
Answer: ( 1 )
EXPLANATION
No answer description required for this question.

12) The greatest eddy current loss in a DC machine occurs in ………..

  1. yoke
  2. armature
  3. field poles
  4. commutating poles
ANSWER
Answer: ( 2 )
EXPLANATION
Since every part of the armature sees cyclic reversals in the magnetic flux direction. It is potentially subjected to more severe eddy current losses than the field pole shoes. Hence armature is invariably laminated to reduce the eddy current loss.

13) The voltage drop at the brushes of a DC machine is …..

  1. 2 volts
  2. 3 volts
  3. 4 volts
  4. 6 volts
ANSWER
Answer: ( 1 )
EXPLANATION
No answer description required for this question.

14) The carbon brushes are used in a DC machine because

  1. carbon lubricates and polishes the commutator
  2. contact resistance is decrease
  3. carbon is cheap
  4. none of the above
ANSWER
Answer: ( 1 )
EXPLANATION
No answer description required for this question.

15) The DC machine armature winding is ………. winding

  1. an open circuit
  2. a closed circuit
  3. partly open circuit and partly closed circuit
  4. none of the above
ANSWER
Answer: ( 2 )
EXPLANATION
No answer description required for this question.

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