Single Phase Induction Motors MCQ

Test your knowledge with important Single Phase Induction Motors MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30 + more Single Phase Induction Motors MCQs at Bissoy

• In case of a shaded pole motor the direction of rotation of the motor is
  ক

  from main pole to shaded pole

  খ

  from shaded pole to main pole

  গ

  either of the above depending on voltage

  ঘ

  either of the above depending on power factor
• The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it
  ক

  improves the efficiency

  খ

  helps the rotor teeth to remain under the stator teeth

  গ

  helps in reducing the tendency of the rotor teeth to remain under the stator teeth

  ঘ

  improves the power factor
• If starting winding of a single-phase induction motor is left in the circuit, it will
  ক

  run faster

  খ

  spark at light loads

  গ

  draw excessive current and overheat

  ঘ

  run slower
• A capacitor-start single phase induction motor is switched on to supply with its capa-citor replaced by an inductor of equivalent reactance value. It will
  ক

  start and then stop

  খ

  start and run slowly

  গ

  start and run at rated speed

  ঘ

  not start at all
• Which of the following motors has highest starting torque ?
  ক

  Repulsion motor

  খ

  Shaped pole motor

  গ

  Capacitor-start motor

  ঘ

  Split-phase motor
• Which of the following motor will give the highest starting torque ?
  ক

  D.C. shunt motor

  খ

  Schrage motor

  গ

  Repulsion start and induction run motor

  ঘ

  Universal motor
• In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will
  ক

  Become unstable

  খ

  Draw excessive armature current and may burn out

  গ

  Fall out of synchronism and come to stand still

  ঘ

  Run as induction motor
• The rotor of a hysteresis motor is made of
  ক

  aluminium

  খ

  cast iron

  গ

  chrome steel

  ঘ

  copper
• Locked rotor current of a shaded pole motor is
  ক

  equal to full load current

  খ

  less than full load current

  গ

  slightly more than full load current

  ঘ

  several times the full load current
• A universal motor can run on
  ক

  D.C. only

  খ

  D.C. only

  গ

  either A.or D.C.

  ঘ

  none of the above
• If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open then
  ক

  motor will not come up to speed

  খ

  motor will not carry the load

  গ

  current drawn by the motor will be excessively high

  ঘ

  electrolytic capacitor will, in all probability, suffer break down
• If a particular application needs high speed and high starting torque, then which of the following motor will bepreferred ?
  ক

  Universal motor

  খ

  Shaded pole type motor

  গ

  Capacitor start motor

  ঘ

  Capacitor start and run motor
• The motor used for the compressors is
  ক

  d.c. series motor

  খ

  shaded pole motor

  গ

  capacitor-start capacitor-run motor

  ঘ

  reluctance motor
• Most of the fractional horsepower motors have either
  ক

  hard and annealed bearings

  খ

  ball or roller bearings

  গ

  soft and porous bearings

  ঘ

  plain or sleeve bearings
• In split phase motor main winding is of
  ক

  thin wire placed at the top of the slots

  খ

  thin wire placed at the bottom of the slots

  গ

  thick wire placed at the bottom of the slots

  ঘ

  thick wire placed at the top of the? slots
• The repulsion start induction run motor is used because of
  ক

  good power factor

  খ

  high efficiency

  গ

  minimum cost

  ঘ

  high starting torque
• If the capacitor of a single-phase motor is short-circuited
  ক

  the motor will not start

  খ

  the motor will run

  গ

  the motor will run in reverse direction

  ঘ

  the motor will run in the same direction at reduced r.p.m.
• The speed/load characteristics of a universal motor is same as that of
  ক

  D.C. motor

  খ

  D.C. shunt motor

  গ

  D.series motor

  ঘ

  none of the above
• Hysteresis motor is particularly useful for high-quality record players and tape-recorders because
  ক

  it revolves synchronously

  খ

  it is not subject to any magnetic or mechanical vibrations

  গ

  it can be easily manufactured in extremely small sizes of up to 1 W output

  ঘ

  it develops hysteresis torque which is extremely steady both in amplitude and phase
• A shaded pole motor can be used for
  ক

  toys

  খ

  hair dryers

  গ

  circulators

  ঘ

  any of the above
• If a single phase induction motor runs slower than normal, the most likely defect is
  ক

  worn bearings

  খ

  short-circuit in the winding

  গ

  open-circuit in the winding

  ঘ

  none of the above
• Which of the following single-phase motors has relatively poor starting torque ?
  ক

  Universal motor

  খ

  Repulsion motor

  গ

  Capacitor motor

  ঘ

  All single phase motors have zero starting torque
• Which of the following statements regarding hysteresis motor is in incorrect ?
  ক

  It is extremely sensitive to fluctuations in supply voltage

  খ

  Its high starting torque is due to its high rotor hysteresis loss

  গ

  It is extremely quiet in operation

  ঘ

  It accelerates from rest to full-speed almost instantaneously
• Which of the following statements regarding single-phase induction motoris correct ?
  ক

  It requires only one winding

  খ

  It can rotate in one direction only

  গ

  It is self-starting

  ঘ

  It is not self-starting
• Burning out of winding is due to
  ক

  short circuited capacitor

  খ

  capacitor value hiving changed

  গ

  open circuiting of capacitor

  ঘ

  none of the above
• Centrifugal switch disconnects the auxiliary winding of the motor at about ____ percent of synchronous speed
  ক

  30 to 40

  খ

  70 to 80

  গ

  80 to 90

  ঘ

  100
• In repulsion motor direction of rotation of motor
  ক

  Is opposite to that of brush shift

  খ

  Is the same as that of brush shift

  গ

  Is independent of brush shift

  ঘ

  None
• In a universal motor, the most common cause of brush sparking is
  ক

  open armature winding

  খ

  shorted armature winding

  গ

  shorted field winding?

  ঘ

  high commutator mica

  ঙ

  all of the above
• Which of the following statements regarding repulsion-start induction motor is incorrect ?
  ক

  It requires more maintenance of commutator and other mechanical devices

  খ

  It makes quite a bit of noise on starting

  গ

  In fractional horse power motors, it has replaced the capacitor motors

  ঘ

  It is not easily reversed
• Which of the following statements regarding a reluctance motor is incorrect ?
  ক

  It cannot be reversed, ordinarily

  খ

  It requires no D.C. field excitation for its operation

  গ

  It is nothing else but a single-phase, salient pole synchronous-induction motor

  ঘ

  Its squirrel cage-rotor is of unsym-metrical magnetic construction in order to vary reluc-tance path between stator and rotor