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.Management Sciences
Category: Single Phase Induction Motors
If a D.C. series motor is operated on A.C. supply, it will____________?
A. spark excessively
B. have poor efficiency
C. have poor power factor
D. all of the above
Which motor is normally free from mechanical and magnetic vibrations ?
A. Split phase motor
B. Universal motor
C. Hysteresis motor
D. Shaded pole motor
A shaded pole motor does not possess___________?
A. centrifugal switch
B. capacitor
C. commutator
D. all of the above
Which of the following motors is preferred for tape-recorders ?
A. Shaded pole motor
B. Hysteresis motor
C. Two value capacitor motor
D. Universal motor
Which of the following motors is used in tape-recorders ____________?
A. Hysteresis motor
B. Reluctance motor
C. Capacitor-run motor
D. Universal motor
In a capacitor start motor, the phase displacement between starting and running winding can be nearly__________?
A. 10°
B. 30°
C. 60°
D. 90°
The repulsion-start induction-run motor is used because of___________?
A. good power factor
B. high efficiency
C. minimum cost
D. high starting torque
In repulsion motor, zero torque is developed when___________?
A. brush axis is 45° electrical to field axis
B. brush axis coincides with the field axis
C. brush axis is 90° electrical to field axis
D. both B. and (c)
The range of efficiency for shaded pole motors is______________?
A. 95% to 99%
B. 80% to 90%
C. 50% to 75%
D. 5% to 35%
Which of the following statements regarding hysteresis motor is in incorrect?
A. It is extremely sensitive to fluctuations in supply voltage
B. Its high starting torque is due to its high rotor hysteresis loss
C. It is extremely quiet in operation
D. It accelerates from rest to full-speed almost instantaneously
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