Single phase induction motors

31. The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it

improves the efficiency
helps the rotor teeth to remain under the stator teeth
helps in reducing the tendency of the rotor teeth to remain under the stator teeth
improves the power factor

Detailed SolutionThe rotor slots, in an induction motor, are usually not quite parallel to the shaft because it

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

Reluctance motor
Series motor
Repulsion motor
Universal motor

Detailed SolutionWhich of the following single-phase motors is suitable for timing and control purposes ?

33. The motor used on small lathes is usually

universal motor
D.
shunt motor C. single-phase capacitor run motor
3-phase synchronous motor

Detailed SolutionThe motor used on small lathes is usually

34. Which of the following motors has two separate windings on the motor ?

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

Detailed SolutionWhich of the following motors has two separate windings on the motor ?

35. As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for

fans
blowers
sound equipment
mixer grinders

Detailed SolutionAs hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for

36. Which of the following motors is used for unity power factor ?

Hysteresis motor
Schrage motor
Universal motor
Reluctance motor

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

37. In a shaded pole motor, the shading coil usually consist of

a single turn of heavy wire which is in parallel with running winding
a single turn of heavy copper wire which is short-circuited and carries only induced current
a multilayer fine gauge copper wire in parallel with running winding
none of the above

Detailed SolutionIn a shaded pole motor, the shading coil usually consist of

38. In repulsion motor, zero torque is developed when

brush axis is 45° electrical to field axis
brush axis coincides with the field axis
brush axis is 90° electrical to field axis
both (B) and (C)

Detailed SolutionIn repulsion motor, zero torque is developed when

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

It requires only one winding
It can rotate in one direction only
It is self-starting
It is not self-starting

Detailed SolutionWhich of the following statements regarding single-phase induction motoris correct ?

40. Torque developed by a single phase induction motor at starting is

pulsating
uniform
none of the above
nil

Detailed SolutionTorque developed by a single phase induction motor at starting is

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