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EEE :: Single Phase Induction Motors

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

  2. A.

     It is similar to reluctance motor

    B.

     It is basically an induction motor and not a synchronous one

    C.

     So far as its basic working principle is concerned, it is similar to shaded pole motor

    D.

     the air-gap between rotor and salient poles is non- uniform


  3. For which of the applications a reluctance motor is preferred ?

  4. A.

     Electric shavers

    B.

     Refrigerators

    C.

     Signalling and timing devices

    D.

     Lifts and hoists


  5. The electric motor used in portable drills is

  6. A.

     capacitor run motor

    B.

     hysteresis motor

    C.

     universal motor

    D.

     repulsion motor


  7. In A.C. series motor compensating winding is employed to

  8. A.

     reduce the effects of armature reaction

    B.

     increase the torque

    C.

     reduce sparking at the brushes

    D.

     none of the above


  9. A centrifugal switch is used to disconnect starting winding when motor has

  10. A.

     run for about 1 minute

    B.

     run for about 5 minutes

    C.

     picked up about 50 to 70 per cent of rated speed

    D.

     picked up about 10 to 25 per cent of rated speed


  11. In a A.C. series motor armature coils are usually connected to commutator

  12. A.

     through resistance

    B.

     through reactances

    C.

     through capacitors

    D.

     solidly


  13. Direction of rotation of a split phase motor can be reversed by reversing the connection of

  14. A.

     running winding only

    B.

     starting winding only

    C.

     either (A) or (B)

    D.

     both (A) and (B)


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

  16. A.

     Split motor

    B.

     Shaded-pole motor

    C.

     Reluctance motor

    D.

     None of these


  17. In which single-phase motor, the rotor has no teeth or winding ?

  18. A.

     Split phase motor

    B.

     Reluctance motor

    C.

     Hysteresis motor

    D.

     Universal motor


  19. In a shaded pole single-phase motor, the revolving field is produced by the use of

  20. A.

     inductor

    B.

     capacitor

    C.

     resistor

    D.

     shading coils