online mcq-Single Phase Motors Part One

Single Phase Motors Part One

Instructions: Click the answer button to see the correct answer.

  1. A capacitor start single phase induction motor will usually have a power factor of
    1. 0.6 lagging.
    2. 0.6 leading
    3. unity
    4. 0.8 leading

    Answera

  2. A capacitor start, capacitor run single phase induction motor is basically a
    1. ac series motor
    2. 2 phase induction motor
    3. 3 phase induction motor.
    4. 3 phase induction motor.

    Answerb

  3. The starting torque of a capacitor start motor is
    1. zero
    2. more than rated torque.
    3. low
    4. same as rated torque

    Answerc

  4. The torque developed by a split phase motor is proportional to
    1. Cosine of angle between lm and Is
    2. Sine of angle between lm and ls
    3. Auxiliary winding current,Is
    4. Main winding current, Im

    Answerb

  5. A
    capacitor start single phase induction motor is switched on the supply
    with its capacitor replaced by an inductor of equivalent reactance
    value. It will

    1. start and then stall
    2. start and run
    3. none of the above.
    4. not start

    Answerd

  6. The starting capacitor of a single phase motor is
    1. None of the above.
    2. Electrolytic capacitor
    3. Ceramic capacitor
    4. Paper capacitor

    Answerb

  7. Which of the following is the most economical method of starting a single phase motor ?
    1. Capacitance start method
    2. Split-phase method.
    3. Inductance start method
    4. Resistance start method

    Answera

  8. The number of turns in the starting winding of a capacitor start motor as compared to that for split phase motor is
    1. more
    2. less
    3. none of the above.
    4. same

    Answera

  9. In a split phase motor, the ratio of number of turns for starting winding to that for running winding is
    1. 2.0
    2. more than 1
    3. less than 1.
    4. 1.0

    Answerc

  10. A single phase motor generally used for small air compressor is
    1. universal motor
    2. shaded pole motor.
    3. reluctance motor
    4. capacitor start capacitor run motor

    Answerd

  11. Out of the following motors, which will give the highest starting torque ?
    1. All have zero starting torque.
    2. Universal motor
    3. Capacitor start motor
    4. Shaded pole motor

    Answerc

  12. Which single phase ac motor will you select for record players and tape recorders ?
    1. Reluctance motor
    2. Shaded pole motor
    3. Hysteresis motor
    4. Two value capacitor motor.

    Answerc

  13. A universal motor is one
    1. which can operate on ac as well as dc voltage
    2. which can work as single phase or three phase motor.
    3. which can run on any value of supply voltage
    4. which has infinitely varying speed

    Answera

  14. Under normal operating conditions which motor can run at 5000 rpm ?
    1. Universal motor
    2. Induction motor
    3. Synchronous motor
    4. No motor can give 5000 rpm.

    Answera

  15. The motor used in household refrigerators is
    1. single phase induction motor.
    2. dc series motor
    3. universal motor
    4. dc shunt motor

    Answera

  16. Single phase motors are commercially manufactured up to
    1. 5 H.P
    2. 2 H.P
    3. 1 H.P
    4. 8 H.P

    Answerb

  17. The direction of rotation of universal motor can be reversed by
    1. reversing the supply terminals
    2. interchanging the brush leads
    3. switching over from ac to dc
    4. any of the above.

    Answerb

  18. A universal motor operates on
    1. constant speed and varying load
    2. synchronous speed with varying load
    3. constant load and varying speed
    4. approximately constant speed and load

    Answerd

  19. Which of the following single phase motors will operate at high power factor ?
    1. capacitor start motor.
    2. shaded pole motor
    3. split phase motor
    4. capacitor run motor

    Answerd

  20. A motor suitable for signaling device is
    1. dc shunt motor
    2. induction motor
    3. dc series motor
    4. reluctance motors.

    Answerd

  21. Which capacitor is preferred in case of single phase motor
    1. Ceramic capacitor
    2. Electrolytic capacitor.
    3. Paper capacitor
    4. Mica capacitor

    Answerb

  22. The motor used for driving the record player deck is
    1. hysteresis motor
    2. dc shunt motor.
    3. dc series motor
    4. synchronous motor

    Answera

  23. When a motor speed of 5000 rpm is required, which motor will you select ?
    1. Shaded pole motor
    2. Hysteresis motor
    3. Universal motor.
    4. Capacitor start motor

    Answerc

  24. As compared to other single phase ac motors a universal motor has
    1. high horse power/kg ratio
    2. all of the above.
    3. highest efficiency on 50 Hz supply
    4. speed ratio of 2: 1 on ac/dc

    Answera

  25. When a universal motor is operated on no load, its speed is limited by
    1. supply voltage frequency
    2. armature weight
    3. armature reaction
    4. windage and friction

    Answerd

  26. Which of the following applications make use of a universal motor ?
    1. Lathe machines.
    2. Oil expeller
    3. Portable tools
    4. Floor polishing machine

    Answerc

  27. In portable tools the speed of the driven shaft is reduced by
    1. Fluid coupling.
    2. Chain drive
    3. Gearing
    4. Belt drive

    Answerc

  28. For ceiling fans generally the single phase motor used is
    1. permanent capacitor type.
    2. capacitor start type
    3. split phase type
    4. capacitor start and run type

    Answera

  29. In case of split phase motors the phase shift is usually limited to
    1. 60 degrees
    2. 3 degrees
    3. 150 degrees
    4. 90 degrees

    Answerb

  30. The capacitance of a small single phase motor will be of the order of
    1. Few hundred farads
    2. Micro or pico farads.
    3. Farads
    4. Kilo farads

    Answerb

  31. The type of starting relay used on single phase hermetic motor is
    1. any of the above
    2. timing relay
    3. hot wire relay
    4. voltage coil relay

    Answerd

  32. Reluctance motors are
    1. doubly excited
    2. either doubly excited or singly excited
    3. none of the above.
    4. singly excited

    Answerd

  33. Electric motors are generally designed to have maximum efficiency at
    1. full load
    2. near full load
    3. half load
    4. near half load.

    Answerb

  34. Which of the following is non-reversible motor ?
    1. Permanent split capacitor motor.
    2. Resistance start split phase motor
    3. Universal motor
    4. Capacitor start split phase motor

    Answerb

  35. Which motor is generally used for electric shavers ?
    1. Reluctance motor
    2. Hysteresis motor
    3. Universal motor.
    4. Shaded pole motor

    Answerc

  36. The motor useful for signaling and timing device is
    1. Shaded pole motor
    2. Reluctance motor
    3. Hysteresis motor
    4. Two value capacitor motor.

    Answerb

  37. A motor generally used in toys is
    1. Reluctance motor.
    2. Shaded pole motor
    3. Two value capacitor motor
    4. Hysteresis motor

    Answerb

  38. Single phase motors generally get over heated due to
    1. Overloading
    2. Any of these.
    3. Short windings
    4. Bearing troubles

    Answerb

  39. Which of the following is a reversible motor ?
    1. Capacitor start split phase motor
    2. None of these
    3. Universal motor
    4. Both

    Answerd

  40. Which of the following motors will operate at high power factor ?
    1. Capacitor start motor
    2. Capacitor run motor
    3. Universal motor
    4. Split phase motor

    Answerb

  41. Which of the following statements about reluctance motor is not true ?
    1. It needs no dc excitation for its rotor
    2. It runs at constant speed
    3. It can operate on ac as well as dc.
    4. It is self starting

    Answerc

  42. The rotor for a hysteresis motor
    1. has high hysteresis loss
    2. has high retentivity
    3. should have all these properties.
    4. is made of chrome steel

    Answerc

  43. The speed of a universal motor can be controlled by
    1. introducing a variable resistance in series with the motor
    2. any of these
    3. tapping the field at various points
    4. centrifugal mechanisms

    Answerb

  44. What could be the smallest size of a universal motor?
    1. any of these
    2. 1/2000 HP.
    3. 1/20 HP
    4. 1/10 HP

    Answerc

  45. The starting torque of a single phase induction motor is
    1. high
    2. zero.
    3. low
    4. uniform

    Answerb

  46. The short coming of repulsion motor is
    1. tendency to spark at brushes
    2. low power factor
    3. variation of speed with load
    4. all of these

    Answerd

  47. The disadvantage of shaded pole motor is
    1. low efficiency
    2. all of these
    3. very little over load capacity
    4. low starting torque’

    Answerb

  48. The efficiency of shaded pole motor is in the range
    1. 70 to 80 percent
    2. 5 to 35 percent.
    3. 50 to 70 percent
    4. 80 to 95 percent

    Answerb

  49. For domestic sewing machine the size of the motor required will be
    1. 10-15 watts
    2. 15-25 watts
    3. 100-150 watts
    4. 250 to 750 watts.

    Answerc

  50. A ceiling fan of 1400 mm sweep will have motor rating of
    1. 50 to 70 watts
    2. 120 to 180 watts
    3. 250 to 500 watts
    4. 10 to 15 watts

    Answerb

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2 Comments

  1. Raju Rajput November 5, 2017
    • Harikesh Yadav November 5, 2017

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