DC Motors MCQ - Electrician (Set-1) with Answers

DC Motors MCQ - Electrician (Set-1) with Answers

41) A 220 V D.C. motor having an armature resistance of 0.2 ohm and back emf 215 V, It draws a current of :

Answer is:

25 amps

42) The armature resistance of a DC machine will be in the order of :

Answer is:

0.1 to 1 ohm

43) The carbon brushes of DC machines become shorter by wearing out during the running time of the machine. At what length do you have to change the brushes ?

Answer is:

1/3 of the original length

44) The supply terminals of a D.C. shunt motor are reversed. What will be the effect on the motor ?

Answer is:

It will run in the same direction

45) What will be the consequences if the field circuit of a D.C. shunt motor is opened when the motor is running at no load condition ?

Answer is:

The motor speed could become dangerously high

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