Single Phase Induction Motor mcq objective questions and answers part1

Q1. In a split phase motor, the ratio of number of turns for starting winding to that for running winding is
(A) very high
(B) more than 1
(C) 1
(D) less than 1.

Q2. Which single phase ac motor is commonly used for record players and tape recorders?
(A) Hysteresis motor
(B) Shaded pole motor
(C) Reluctance motor
(D) Two value capacitor motor.

Q3. Torque developed by a single phase induction motor at starting is
(A) pulsating
(B) uniform
(C) none of the above
(D) zero

Q4. As hysteresis motors are free from mechanical and magnetic vibrations therefore these are considered as suitable for
(A) fans
(B) blowers
(C) sound equipment
(D) mixer grinders

Q5. Which of the following motors will operate at high power factor ?
(A) Shaped pole motor
(B) Split phase motor
(C) Capacitor start motor
(D) Capacitor run motor

Q6. The disadvantage of shaded pole motor is
(A) low starting torque
(B) low efficiency
(C) very little over load capacity
(D) all of these

Q7. The rotor for a hysteresis motor
(A) is made of chrome steel
(B) has high retentivity
(C) has high hysteresis loss
(D) All of these

Q8. Single phase induction motor usually operates on
(A) 0.6 power factor lagging
(B) 0.8 power factor lagging
(C) 0.9 power factor leading
(D) unity power factor

Q9. A single-phase induction motor is
(A) self-starting with high torque
(B) self-starting with low torque
(C) non-self-starting with low torque
(D) non-self-starting with high torque

Q10. A reluctance motor is preferred for which of the applications?
(A) Electric shavers
(B) Refrigerators
(C) Signalling and timing devices
(D) Lifts and hoists

Q11. A hysteresis motor works on the principle of
(A) hysteresis loss
(B) magnetisation of rotor
(C) eddy current loss
(D) electromagnetic induction

Q12. The power factor of a single-phase induction motor is usually
(A) lagging
(B) always leading
(C) unity
(D) unity to 0.8 leading

Q13. The range of efficiency for shaded pole motors is
(A) 90% to 95%
(B) 80% to 90%
(C) 60% to 75%
(D) 5% to 35%

Q14. The direction of rotation of an hysteresis motor is determined by
(A) interchanging the supply leads
(B) position of shaded pole with respect to main pole
(C) retentivity of the rotor material
(D) none of these

Q15. If a single phase motor runs slow, the probable cause may be
(A) overload
(B) low frequency
(C) low voltage
(D) any of the above

Q16. The rotor of which motor does not have winding on it?
(A) Universal motor
(B) Hysteresis motor
(C) Reluctance motor
(D) Repulsion motor.

Q17. In a hysteresis motor, the position of shaded pole with respect to main pole determines
(A) speed of motor
(B) direction of rotation
(C) hysteresis loss
(D) no load rpm.

Q18. Which of the following motor will give relatively high starting torque ?
(A) Capacitor start motor
(B) Capacitor run motor
(C) Split phase motor
(D) Shaded pole motor

Q19. In a capacitor start motor, the phase displacement between starting and running winding can be nearly
(A) 10°
(B) 30°
(C) 60°
(D) 90°

Q20. If the capacitor of a single-phase motor is short-circuited
(A) the motor will not start
(B) the motor will run
(C) the motor will run in reverse direction
(D) the motor will run in the same direction at reduced r.p.m.