Single Phase Induction Motors

31. 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

Correct answer: (A)
secondary winding surrounds the primary winding

32. In a hysteresis motor, the rotor must have

  1. retentivity
  2. resistivity
  3. susceptibility
  4. none of the above

Correct answer: (A)
retentivity

33. In a shaded pole motor, the shading coil usually consist of

  1. a single turn of heavy wire which is in parallel with running winding
  2. a single turn of heavy copper wire which is short-circuited and carries only induced current
  3. a multilayer fine gauge copper wire in parallel with running winding
  4. none of the above

Correct answer: (B)
a single turn of heavy copper wire which is short-circuited and carries only induced current

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

  1. inductor
  2. capacitor
  3. resistor
  4. shading coils

Correct answer: (D)
shading coils

35. In a single phase motor the centrifugal switch

  1. disconnects auxiliary winding of the motor
  2. disconnects main winding of the motor
  3. reconnects the main winding the motor
  4. reconnects the auxiliary winding of the motor

Correct answer: (A)
disconnects auxiliary winding of the motor

36. 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

Correct answer: (A)
the starting winding is connected through a centrifugal switch

37. In a split phase motor, the running winding should have

  1. high resistance and low inductance
  2. low resistance and high inductance
  3. high resistance as well as high inductance
  4. low resistance as well as low inductiance

Correct answer: (B)
low resistance and high inductance

38. In a two value capacitor motor, the capacitor used for running purposes is

  1. air capacitor
  2. paper spaced oil filled type
  3. ceramic type
  4. a.c. electrolytic type

Correct answer: (B)
paper spaced oil filled type

39. 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

Correct answer: (E)
all of the above

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

  1. reduce the effects of armature reaction
  2. increase the torque
  3. reduce sparking at the brushes
  4. none of the above

Correct answer: (C)
reduce sparking at the brushes

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