single phase induction motors MCQs – Page 5

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

single phase induction motors Mcqs

81. If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open then____________?
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A. current drawn by the motor will be excessively high

B. electrolytic capacitor will, in all probability, suffer break down

C. motor will not come up to speed

D. motor will not carry the load

82. A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will______________?
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A. not start at all

B. start and run slowly

C. start and then stop

D. start and run at rated speed

83. A universal motor is one which______________?
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A. can be operated either on D.C. or A.C. supply at approximately the same speed and output

B. can be marketed internationally

C. runs at dangerously high speed on no-load

84. The speed of a universal motor is usually reduced by using____________?
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A. gearing

B. chains

C. belts

D. brakes

85. A hysteresis motor works on the principle of__________?
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A. electromagnetic induction

B. hysteresis loss

C. eddy current loss

D. magnetisation of rotor

86. In a shaded pole motor, the shading coil usually consist of___________?
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A. a single turn of heavy copper wire which is short-circuited and carries only induced current

B. a multilayer fine gauge copper wire in parallel with running winding

C. none of the above

D. a single turn of heavy wire which is in parallel with running winding

87. Which of the following motor will give relatively high starting torque ___________?
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A. Shaded pole motor

B. Capacitor run motor

C. Capacitor start motor

D. Split phase motor

88. A.C. series motor as compared to D.C. series motor has__________?
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A. all of the above

B. less air gap

C. less number of field turns

D. more number of armature turns

E. smaller brush width

89. Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because_____________?
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A. it has almost non-destructible capacitor

B. it has low starting as well as running currents at relatively high power factor

C. it is quiet in operation

D. it is comparatively cheaper

90. A shaded pole motor can be used for_____________?
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A. circulators

B. any of the above

C. toys

D. hair dryers

91. Which of the following motors is used for unity power factor ?
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A. Reluctance motor

B. Hysteresis motor

C. Schrage motor

D. Universal motor

92. The speed/load characteristics of a universal motor is same as that of_____________?
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A. none of the above

B. D.C. series motor

C. D.C. shunt motor

D. A.C. motor

93. In a ceilingfan employing capacitor run motor____________?
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A. secondary winding surrounds the primary winding

B. primary winding surrounds the secondary winding

C. both are usual arrangements

D. none of the above

94. Which of the following motors is used in tape-recorders ____________?
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A. Hysteresis motor

B. Reluctance motor

C. Universal motor

D. Capacitor-run motor

95. To reverse the direction of rotation of acapacitor start motor while it is running we should___________?
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A. disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding

B. disconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding

C. reverse the direction of connections of the auxiliary winding and immediately connect it to supply

D. reverse the direction of connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply

96. If a particular application needs high speed and high starting torque, then which of the following motor will be preferred ?
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A. Shaded pole type motor

B. Capacitor start and run motor

C. Capacitor start motor

D. Universal motor

97. Which of the following single-phase motors has relatively poor starting torque ?
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A. Universal motor

B. All single phase motors have zero starting torque

C. Repulsion motor

D. Capacitor motor

98. Speed control of a universal motor is achieved by__________?
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A. all of the above methods

B. applying variable voltage by means of silicon controlled rectifier

C. applying variable voltage by means of variable auto-transformer

D. connecting rheostat in series

E. varying field flux with tapped field windings

99. Which of the following single-phase induction motors is generally used in time phonographs ?
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A. Resistance start

B. Capacitor start capacitor run

C. Shaded pole

D. Universal

100. In a A.C. series motor armature coils are usually connected to commutator____________?
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A. solidly

B. through capacitors

C. through reactances

D. through resistance

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