single phase induction motors MCQs – Page 4

Practise focused single phase induction motors questions with marked answers for exam preparation and subject revision.

single phase induction motors Mcqs

61. Which of the following motor will have relatively higher power factor ?
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A. Capacitor run motor

B. Capacitor start motor

C. Split phase motor

D. Shaded pole motor

62. Most of the fractional horsepower motors have either___________?
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A. soft and porous bearings

B. hard and annealed bearings

C. plain or sleeve bearings

D. ball or roller bearings

63. Single phase induction motor usually operates on__________?
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A. 0.6 power factor lagging

B. unity power factor

C. 0.8 power factor lagging

D. 0.8 power factor leading

64. Which of the following motors has highest starting torque ?
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A. Split-phase motor

B. Capacitor-start motor

C. Shaped pole motor

D. Repulsion motor

65. Which of the following applications always have some load whenever switched on ?
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A. Vacuum cleaners

B. Fan motors

C. All of the above

D. Pistol drills

66. Which of the following statements regarding hysteresis motor is in incorrect?
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A. It accelerates from rest to full-speed almost instantaneously

B. It is extremely quiet in operation

C. It is extremely sensitive to fluctuations in supply voltage

D. Its high starting torque is due to its high rotor hysteresis loss

67. In capacitor start single-phase motors____________?
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A. current in the starting winding lags the voltage

B. current in the starting winding leads the voltage

C. none of the above

D. current in the starting winding is in phase with voltage in running winding

68. The speed control of universal motor used for sewing machines is by____________?
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A. friction

B. varying the resistance

C. tapping the field

D. centrifugal mechanism

69. The rotor of a hysteresis motor is made of___________?
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A. cast iron

B. aluminium

C. chrome steel

D. copper

70. Which of the following motors is inherently self starting ?
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A. None of these

B. Split motor

C. Shaded-pole motor

D. Reluctance motor

71. Which of the following motors has two separate windings on the motor ?
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A. None of the above

B. Repulsion start induction run motor

C. Repulsion motor

D. Repulsion induction motor

72. For which of the applications a reluctance motor is preferred ?
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A. Lifts and hoists

B. Electric shavers

C. Refrigerators

D. Signalling and timing devices

73. The shaded pole motor is used for__________?
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A. high starting torque

B. medium starting torque

C. low starting torque

D. very high starting torque

74. The starting winding of a single-phase motor is placed in_________?
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A. armature

B. field

C. rotor

D. stator

75. In a shaded pole single-phase motor, the revolving field is produced by the use of_________?
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A. inductor

B. resistor

C. shading coils

D. capacitor

76. If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in_________?
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A. none of the above

B. overloading of running winding

C. damage to the starting winding

D. damage to the centrifugal switch

77. A reluctance motor____________?
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A. all of the above

B. is self-starting

C. is constant speed motor

D. needs no D.C. excitation

78. A shaded pole motor does not possess___________?
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A. capacitor

B. commutator

C. all of the above

D. centrifugal switch

79. Which type of load is offered by cranes and hoists ?
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A. Reversing, light start

B. Non-reversing, no-load start

C. Reversing, heavy start

D. Gradually varying load

80. The wattage of motor for driving domestic sewing machine will be around__________?
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A. 5 to 10 W

B. 100 to 150 W

C. 10 to 30 W

D. 40 to 75 W

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