DC Motors Questions and Answers - Electronic Engineering
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DC MOTORS Questions and Answers pdf free download. DC MOTORS – Electrical Engineering Multiple Choice Questions and Answers.
- The direction of rotation will reverse
- Motor will stop
- Motor will run at its normal speed in the same direction as it was running
- Motor will run at speed lower than the normal speed in the same direction
Question 1: What will happen if supply terminals of D.C. shunt motor are interchanged?
Answers: Motor will run at its normal speed in the same direction as it was running
- production of opposing back EMF Eb in the armature
- application of Fleming's left-hand rule
- use of commutator
- input energy from supply
Question 2: In a motor, energy conversion would not have been possible but for the?
Answers: production of opposing back EMF Eb in the armature
- rotor laminations
- pole shoes
- end-plates
- Commutator
Question 3: In a DC motor constant torque is produced due to?
Answers: commutator
- 100%
- less than 50%
- 80 to 90%
- 60 to 70%
Question 4: If conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be?
Answers: less than 50%
- Brush contact loss
- Core Loss
- none of the above
- Friction and windage loss
Question 5: Which of the following loss of D.C. motor decreases with increase in load ?
Answers: none of the above
- constant torque drive
- variable torque drive
- variable power drive
- constant power drive
Question 6: Speed control by the variation of flux, in a D.C. shunt motor, will give?
Answers: constant power drive
- a stronger commutating field is needed at low speed than at high speed
- a weaker commutating field is needed at low speed than at high speed
- same commutating field is needed at low speed than at high speed
- none of the above is correct
Question 7: In variable speed motor?
Answers: a weaker commutating field is needed at low speed than at high speed
- field control method
- field divertor method
- voltage control method
- armature resistance control method
Question 8: Ward-Leonard control is basically a?
Answers: voltage control method
- in both directions
- in one direction
- below normal speed only
- above normal speed only
Question 9: Speed control by Ward Leonard method gives uniform speed variation?
Answers: in both directions
- Hopkinson's test
- Field's test
- Swinburne's test
- Brake test
Question 10: In which of the following tests only one motor is required?
Answers: Brake test
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Total Questions Attempted: 0
Correct: 0 Wrong: 0
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