Single phase induction motors

1. The purpose of stator winding in the compensated repulsion motor is to

provide mechanical balance
improve power factor and provide better speed regulation
prevent hunting in the motor
eliminate armature reaction

Detailed SolutionThe purpose of stator winding in the compensated repulsion motor is to

2. Which of the following motors can be used for unity power factor ?

Capacitor run motor
Shaded pole motor
Hysteresis motor
Schrage motor

Detailed SolutionWhich of the following motors can be used for unity power factor ?

3. Which of the following motors can be run on AC. as well as D.C. supply ?

Universal motor
Repulsion motor
as well as
Reluctance motor

Detailed SolutionWhich of the following motors can be run on AC. as well as D.C. supply ?

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

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

Detailed SolutionWhich of the following statements regarding a reluctance motor is incorrect ?

5. The range of efficiency for shaded pole motors is

95% to 99%
80% to 90%
50% to 75%
5% to 35%

Detailed SolutionThe range of efficiency for shaded pole motors is

6. In

reduce the effects of armature reaction
increase the torque
series motor compensating winding is employed to A. reduce the effects of armature reaction B. increase the torque C. reduce sparking at the brushes
none of the above

Detailed SolutionIn

7. Short-circuiter is used in

Repulsion induction motor
Repulsion motor
Repulsion start induction run motor
None of the above

Detailed SolutionShort-circuiter is used in

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

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

Detailed SolutionWhich of the following statements regarding hysteresis motor is in incorrect ?

9. The capacitors used in single-phase capacitor motors have no

voltage rating
dielectric medium
polarity marking
definite value

Detailed SolutionThe capacitors used in single-phase capacitor motors have no

10. In case of a shaded pole motor the direction of rotation of the motor is

from main pole to shaded pole
from shaded pole to main pole
either of the above depending on voltage
either of the above depending on power factor

Detailed SolutionIn case of a shaded pole motor the direction of rotation of the motor is

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