Objective Questions on Single Phase Motors | Part 2


16. Single phase motors are commercially manufactured up to

  A   1 H.P.
  B   2 H.P.
  C   5 H.P.
  D   10 H.P.

17. The direction of rotation of universal motor can be reversed by

  A   reversing the supply terminals
  B   switching over from ac to dc
  C   interchanging the brush leads
  D   any of the above.


18. A universal motor operates on

  A   constant speed and varying load
  B   constant load and varying speed
  C   approximately constant speed and load
  D   synchronous speed with varying load.


19. Which of the following single phase motors will operate at high power factor ?

  A   shaded pole motor
  B   capacitor run motor
  C   split phase motor
  D   capacitor start motor.


20. A motor suitable for signaling device is

  A   induction motor
  B   dc shunt motor
  C   dc series motor
  D   reluctance motors.


21. Which capacitor is preferred in case of single phase motor

  A   Paper capacitor
  B   Ceramic capacitor
  C   Mica capacitor
  D   Electrolytic capacitor.


22. The motor used for driving the record player deck is

  A   dc series motor
  B   synchronous motor
  C   hysteresis motor
  D   dc shunt motor.


23. When a motor speed of 5000 rpm is required, which motor will you select ?

  A   Capacitor start motor
  B   Shaded pole motor
  C   Hysteresis motor
  D   Universal motor.


24. As compared to other single phase ac motors a universal motor has

  A   speed ratio of 2   1 on ac/dc
  B   highest efficiency on 50 Hz supply
  C   high horse power/kg ratio
  D   all of the above.


25. When a universal motor is operated on no load, its speed is limited by

  A   armature reaction
  B   armature weight
  C   windage and friction
  D   supply voltage frequency.


26. Which of the following applications make use of a universal motor ?

  A   Floor polishing machine
  B   Oil expeller
  C   Portable tools
  D   Lathe machines.


27. In portable tools the speed of the driven shaft is reduced by

  A   Gearing
  B   Belt drive
  C   Chain drive
  D   Fluid coupling.


28. For ceiling fans generally the single phase motor used is

  A   split phase type
  B   capacitor start type
  C   capacitor start and run type
  D   permanent capacitor type.


29. In case of split phase motors the phase shift is usually limited to

  A   3 degrees
  B   60 degrees
  C   90 degrees
  D   150 degrees.


30. The capacitance of a small single phase motor will be of the order of

  A   Kilo farads
  B   Few hundred farads
  C   Farads
  D   Micro or pico farads.


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