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.Management Sciences
Category: Single Phase Induction Motors
Which of the following motors can be run on AC. as well as D.C. supply ?
A. Universal motor
B. Repulsion motor
C. Synchronous motor
D. Reluctance motor
The power factor of a single-phase induction motor is usually?
A. lagging
B. always leading
C. unity
D. unity to 0.8 leading
Which of the following motors is used in a situation where load increases with speed ?
A. Induction motor
B. Three-phase series motor
C. Schrage motor
D. Hysteresis motor
If a particular application needs high speed and high starting torque, then which of the following motor will be preferred ?
A. Universal motor
B. Shaded pole type motor
C. Capacitor start motor
D. Capacitor start and run motor
After the starting winding of a single phase induction motor is disconnected from supply, it continues to run only on ______________?
A. running winding
B. rotor winding
C. field winding
D. compensating winding
Which of the following single-phase motors is suitable for timing and control purposes ?
A. Reluctance motor
B. Series motor
C. Repulsion motor
D. Universal motor
As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for__________?
A. fans
B. blowers
C. sound equipment
D. mixer grinders
Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because_____________?
A. it is comparatively cheaper
B. it has almost non-destructible capacitor
C. it has low starting as well as running currents at relatively high power factor
D. it is quiet in operation
Which of the following statements regarding a reluctance motor is incorrect ?
A. It cannot be reversed, ordinarily
B. It requires no D.C. field excitation for its operation
C. It is nothing else but a single-phase, salient pole synchronous-induction motor
D. Its squirrel cage-rotor is of unsym-metrical magnetic construction in order to vary reluctance path between stator and rotor
To reverse the direction of rotation of acapacitor start motor while it is running we should___________?
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 connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply
D. reverse the direction of connections of the auxiliary winding and immediately connect it to supply
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