Single Phase Induction Motors

101. Which of the following single-phase induction motors is generally used in time phonographs?

1. Resistance start
2. Capacitor start capacitor run
3. Shaded pole
4. Universal

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102. Which of the following single-phase motors has relatively poor starting torque?

1. Universal motor
2. Repulsion motor
3. Capacitor motor
4. All single phase motors have zero starting torque

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103. Which of the following single-phase motors is suitable for timing and control purposes?

1. Reluctance motor
2. Series motor
3. Repulsion motor
4. Universal motor

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104. Which of the following statements regarding a reluctance motor is incorrect?

1. It cannot be reversed, ordinarily
2. It requires no D.C. field excitation for its operation
3. It is nothing else but a single-phase, salient pole synchronous-induction motor
4. Its squirrel cage-rotor is of unsym-metrical magnetic construction in order to vary reluctance path between stator and rotor

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105. Which of the following statements regarding hysteresis motor is in incorrect?

1. It is extremely sensitive to fluctuations in supply voltage
2. Its high starting torque is due to its high rotor hysteresis loss
3. It is extremely quiet in operation
4. It accelerates from rest to full-speed almost instantaneously

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106. Which of the following statements regarding reluctance-start motor is incorrect?

1. It is similar to reluctance motor
2. It is basically an induction motor and not a synchronous one
3. So far as its basic working principle is concerned, it is similar to shaded pole motor
4. the air-gap between rotor and salient poles is non- uniform

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107. Which of the following statements regarding repulsion-start induction motor is incorrect?

1. It requires more maintenance of commutator and other mechanical devices
2. It makes quite a bit of noise on starting
3. In fractional horse power motors, it has replaced the capacitor motors
4. It is not easily reversed

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108. Which of the following statements regarding single-phase induction motoris correct?

1. It requires only one winding
2. It can rotate in one direction only
3. It is self-starting
4. It is not self-starting

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109. Which of the following statements regarding two value capacitor motor is incorrect?

1. It is a reversing motor
2. It is preferred to permanent-split single-value capacitor motor where frequent reversals are required
3. It has low starting as well as rushing currents
4. It has high starting torque

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110. Which type of load is offered by cranes and hoists?

1. Gradually varying load
2. Non-reversing, no-load start
3. Reversing, light start
4. Reversing, heavy start

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