Single phase induction motors Archives

81. 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

82. 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 ?

83. The motor used on small lathes is usually

universal motor

shunt motor C. single-phase capacitor run motor

3-phase synchronous motor

Detailed SolutionThe motor used on small lathes is usually

84. 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 ?

85. 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

86. 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 ?

87. 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

88. In repulsion motor, zero torque is developed when

brush axis is 45Â° electrical to field axis

brush axis coincides with the field axis

brush axis is 90Â° electrical to field axis

both (B) and (C)

Detailed SolutionIn repulsion motor, zero torque is developed when

89. 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 ?

90. 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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