Single phase induction motors

11. Which motor is normally free from mechanical and magnetic vibrations ?

Split phase motor
Universal motor
Hysteresis motor
Shaded pole motor

Detailed SolutionWhich motor is normally free from mechanical and magnetic vibrations ?

12. Which of the following motors is inherently self starting ?

Split motor
Shaded-pole motor
Reluctance motor
None of these

Detailed SolutionWhich of the following motors is inherently self starting ?

13. In case of high speed universal motor which of the following needs more attention ?

End play
Air gap
Insulation in rotor
Balancing of rotor

Detailed SolutionIn case of high speed universal motor which of the following needs more attention ?

14. When a D.C. series motor is connected to

high inductance of field and armature circuits
induced current in rotor due to variations of flux
series motor is connected to A.C. supply, the power factor will be low because of A. high inductance of field and armature circuits B. induced current in rotor due to variations of flux C. fine copper wire winding
none of the above

Detailed SolutionWhen a D.C. series motor is connected to

15. A universal motor can run on

D.C. only
D.
only B.
none of the above

Detailed SolutionA universal motor can run on

16. In repulsion motor, maximum torque is developed when

brush axis is at 45° electrical to the field axis
brush axis coincides with the field axis
brush axis is at 90° electrical to the field axis
none of the above

Detailed SolutionIn repulsion motor, maximum torque is developed when

17. The wattage rating for a ceiling fan motor will be in the range

200 to 250 W
250 to 500 W
50 to 150 W
10 to 20 W

Detailed SolutionThe wattage rating for a ceiling fan motor will be in the range

18. Which of the following motor will give the highest starting torque ?

D.C. shunt motor
Schrage motor
shunt motor B. Schrage motor C. Repulsion start and induction run motor
Universal motor

Detailed SolutionWhich of the following motor will give the highest starting torque ?

19. Which of the following statements regarding reluctance-start motor is incorrect ?

It is similar to reluctance motor
It is basically an induction motor and not a synchronous one
So far as its basic working principle is concerned, it is similar to shaded pole motor
the air-gap between rotor and salient poles is non- uniform

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

20. Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because

it is comparatively cheaper
it has almost non-destructible capacitor
it has low starting as well as running currents at relatively high power factor
it is quiet in operation

Detailed SolutionTwo-value capacitor motor finds increased application as compressor motor in small home air-conditioners because

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