Single Phase Induction Motors(Electrical Engineering ) Questions and Answers

Question 1. In a split phase motor
  1.    the starting winding is connected through a centrifugal switch
  2.    the running winding is connected through a centrifugal switch
  3.    both starting and running windings are connected through a centrifugal switch
  4.    centrifugal switch is used to control supply voltage
Explanation:-
Answer: Option A. -> the starting winding is connected through a centrifugal switch
Question 2. Which type of load is offered by cranes and hoists ?
  1.    Gradually varying load
  2.    Non-reversing, no-load start
  3.    Reversing, light start
  4.    Reversing, heavy start
Explanation:-
Answer: Option D. -> Reversing, heavy start
Question 3. In a ceilingfan employing capacitor run motor
  1.    secondary winding surrounds the primary winding
  2.    primary winding surrounds the secondary winding
  3.    both are usual arrangements
  4.    none of the above
Explanation:-
Answer: Option A. -> secondary winding surrounds the primary winding
Question 4. Which of the following motors is used in mixies ?
  1.    Repulsion motor
  2.    Reluctance motor
  3.    Hysteresis motor
  4.    Universal motor
Explanation:-
Answer: Option D. -> Universal motor
Question 5. Which of the following motors is preferred for tape-recorders?
  1.    Shaded pole motor
  2.    Hysteresis motor
  3.    Two value capacitor motor
  4.    Universal motor
Explanation:-
Answer: Option B. -> Hysteresis motor
Question 6. Which of the following statements regarding a reluctance motor is incorrect ?
  1.    It cannot be reversed, ordinarily
  2.    It requires no D.C. field excitation for its operation
  3.    It is nothing else but a single-phase, salient pole synchronous-induction motor
  4.    Its squirrel cage-rotor is of unsym-metrical magnetic construction in order to vary reluc-tance path between stator and rotor
Explanation:-
Answer: Option A. -> It cannot be reversed, ordinarily
Question 7. Centrifugal switch disconnects the auxiliary winding of the motor at about ____ percent of synchronous speed
  1.    30 to 40
  2.    70 to 80
  3.    80 to 90
  4.    100
Explanation:-
Answer: Option B. -> 70 to 80
Question 8. In repulsion motor direction of rotation of motor
  1.    Is opposite to that of brush shift
  2.    Is the same as that of brush shift
  3.    Is independent of brush shift
  4.    None
Explanation:-
Answer: Option B. -> Is the same as that of brush shift
Question 9. In a universal motor, the most common cause of brush sparking is
  1.    open armature winding
  2.    shorted armature winding
  3.    shorted field winding?
  4.    high commutator mica
  5.    all of the above
Explanation:-
Answer: Option E. -> all of the above
Question 10. Which of the following statements regarding repulsion-start induction motor is incorrect ?
  1.    It requires more maintenance of commutator and other mechanical devices
  2.    It makes quite a bit of noise on starting
  3.    In fractional horse power motors, it has replaced the capacitor motors
  4.    It is not easily reversed
Explanation:-
Answer: Option C. -> In fractional horse power motors, it has replaced the capacitor motors
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