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MCQ of D.C motor page-1MCQ of D.C motor page-2MCQ of D.C motor page-3MCQ of D.C motor page-4Multiple Choice Question (MCQ) of D.C. Machines page-1Multiple Choice Question (MCQ) of D.C. Machines page-2Multiple Choice Question (MCQ) of D.C. Machines page-3Multiple Choice Question (MCQ) of D.C. Machines page-4Multiple Choice Question (MCQ) of D.C. Machines page-5Multiple Choice Question (MCQ) of D.C. Machines page-6Multiple Choice Question (MCQ) of D.C. Machines page-7Multiple Choice Question (MCQ) of D.C. Machines page-8Multiple Choice Question (MCQ) of D.C. Machines page-9Multiple Choice Question (MCQ) of D.C. Machines page-10MCQ of D.C motor page-5MCQ of D.C motor page-6MCQ of D.C motor page-7MCQ of D.C motor page-8MCQ of D.C motor page-9MCQ of D.C motor page-10MCQ of D.C motor page-11MCQ of D.C motor page-12MCQ of D.C motor page-13MCQ of D.C motor page-14MCQ of D.C motor page-15MCQ of D.C motor page-16MCQ of D.C motor page-17MCQ of D.C motor page-18

Index

SymbolsTransformerRelayPower-SystemBasic-electricalACSR-ConductorCircuit-BreakerInterview-questions-of-Basic-ElectricityInterview-questions-of-transformerInsulatorCurrent-TransformerMCQMCQ-powersystemThermal-power-stationInterview-questions-of-Power-SystemPower-ElectronicsInterview-questions-of-Underground-CableInterview-questions-of-IlluminationIlluminationMCQ-of-ElectronicsMCQ-of-Basic-ElectricalMCQ-of-Transformers MCQ-of-D.C-motor MCQ-of-D.C-generatorsMCQ-Control-SystemMCQ-Measurementsmcq-of-Generation-power-systemMCQ-of-Induction-MotorMCQ-of-Transmission-DistributionMCQ-of-Electrical-MachinesMCQ-of-Alternator-and-Synchronous-MotorsMCQ-Electric-Power

MCQ of D.C motor page-9


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41. A dc series motor

A) may ‘run away’ if the field gets opened
B) is not suitable for high starting torque
C) always runs at constant speed
D) should always be started on load.

Ans : (D)

42. The armature of a shunt motor contains 0.8-ohm resistance. The motor is to run on a 120 V circuit. If the motor is suddenly thrown on the circuit while the armature is standing still (back emf in normal running being 110 V), the current drawn by the motor will be

A) 12.5 A
B) 25 A
C) 250 A
D) 600 A.

Ans : (A)

43. The airgap between stator and armature of an electric motor is kept small in order to

A) provide stronger magnetic field
B) reduced noise
C) facilitate high speed operation without vibrations
D) provide adequate air for cooling the rotor winding.

Ans : (A)

44. Small dc motors upto 5 HP usually have

A) 4 poles
B) 2 poles
C) 6 poles
D) 8 poles.

Ans : (B)

45. Which dc motor has approximately constant speed?

A) shunt motor
B) series motor
C) cumulatively compound motor
D) all of the above.

Ans : (A)

46. A dc generator can be termed as

A) Power line
B) Rotating amplifier
C) Prime moves
D) Power pump.

Ans : (B)

47. A dc shunt motor has rated rmp of 480. Certain industrial application requires this motor to run at 540 rpm for sometime. Which speed control will be desirable

A) Armature current control
B) Ward Leonard control
C) Field resistance control
D) It is not possible to run the motor at more than the rated rpm.

Ans : (C)

48. Which motor will have highest percentage increase of input current, for the same percentage increases in torque?

A) Series motor
B) Shunt motor
C) Cumulatively compound motor
D) All will have same percentage increase.

Ans : (A)

49. Which of the following methods is most effective in finding out the no-load losses in a large dc shunt motor?

A) Leonard test
B) Hopkinson’s test
C) Swinburne’s test
D) Block rotor test.

Ans : (C)

50. A dc shunt motor is designed to run at 450 rpm. In order to run this motor at 600 rpm, the type of control that should be selected is

A) Field resistance control
B) Ward Leonard control
C) Armature circuit resistance control
D) Any of the above.

Ans : (A)


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