Single Phase Induction Motor MCQ

61. In comparison to resistance start induction motor the permanent capacitor motor

(a) is more expensive.
(b) has better power factor.
(c) has better starting torque.
(d) all of the above.

62. In comparison to capacitor-start capacitor-run motor the permanent capacitor motor has

(a) simple construction and low cost.
(b) poor power factor.
(c) poor starting torque.
(d) all of the above.

63. Which of the following statements regarding permanent capacitor motor is false ?

(a) It does not have a centrifugal switch.
(b) It does not have a starting winding and a squirrel cage rotor.
(c) Its auxiliary winding is designed for continuous rating.
(d) It is more sensitive to voltage variations due to its poor running torque.

64. Capacitor-start and capacitor-run motors are used in

(a) hoists.
(b) rolling mills.
(c) mining.
(d) refrigerator. [A.M.I.E. Sec B. Summer 1998]

65. In a shaded pole motor the phase splitting is achieved by placing a shading coil at the slot cut around the

(a) larger part of the pole.
(b) smaller part of the pole.
(c) both the parts of the pole.
(d) any of the above.

66. In a shaded pole motor, the rotating field is developed by using

(a) salient poles.
(b) a capacitor.
(c) shading coils.
(d) damper winding.

67. Shaded pole motor is provided with

(a) laminated salient poles and a squirrel cage rotor.
(b) a commutator.
(c) a capacitor.
(d) a centrifugal switch.

68. In a shaded-pole motor, shading coils are used to

(a) reduce winding losses.
(b) reduce friction losses.
(c) produce rotating magnetic field.
(d) protect against sparking. [U.P.S.C. I.E.S. 1992]

69. In a shaded-pole induction motor, the rotor runs from the

(a) shaded portion to the un-shaded portion of the pole while the flux in the former leads that of the latter.
(b) shaded portion to the un-shaded portion of the pole while the flux in the former lags that in the latter.
(c) un-shaded portion to the shaded portion while the flux in the former leads that in the latter.
(d) un-shaded portion to the shaded portion while the flux in the former lags that in the latter. [U.P.S.C. I.E.S. E.E.-II 2001]

70. Consider the following statements regarding fractional horse power shaded pole motor;

1. Its direction of rotation is from un-shaded to shaded portion of the poles.
2. Its direction of rotation is from shaded to un-shaded portion of the poles.
3. It can remain stalled for short periods without any harm.
4. It has a very poor power factor.

Of these statements
(a) 1,3 and 4 are correct.
(b) 2,3 and 4 are correct.
(c) 2 and 4 are correct.
(d) 1 and 3 are correct. [U.P.S.C. I.E.S. E.E.-II, 1997]

71. Which of the following are the features of a shaded pole motor?

1. Salient pole stator.
2. Uniform air gap.
3. Two stator windings one of which is a short-circuited ring.
4. Squirrel cage rotor.

Select the correct answer using the codes given below:
Codes: (a) 1 and 4.
(b) 2 and 4.
(c) 1, 3 and 4.
(d) 1, 2 and 3. [U.P.S.C. I.E.S. E.E.-II, 1998]

72. Which of the following statements associated with shaded pole induction motor is incorrect ?

(a) It is one of the simplest and cheapest single phase induction motor.
(b) It has squirrel cage type rotor.
(c) It has high operating efficiency.
(d) It has laminated salient poles each provided with its own exciting coil.
(e) It is built in very small ratings (say upto 40 W).

73. In a shaded pole induction motor, locked rotor current is …….. full-load current.

(a) less than
(b) equal to
(c) slightly more than
(d) several times the

74. The direction of rotation of a shaded pole induction motor

(a) cannot be reversed unless there is a provision for shifting of shading coil from one half to the other half of the pole.
(b) can he reversed by interchanging main winding terminals.
(c) can be reversed by interchanging the supply terminals.
(d) can be reversed by open-circuiting the shading rings.

75. The speed of single phase induction motors can be controlled by

(a) varying the applied voltage to the stator winding.
(b) varying the number of poles on the stator.
(c) either (a) or (b).
(d) none of these.

76. The wattage rating for a ceiling motor will be in the range

(a) 50 to 250 W.
(b) 250 to 500 W.
(c) 50 to 150 W.
(d) 10 to 20 W. [A.M.I.E. Sec B. EIec. Machines Summer 1996]

77. The type of single-phase induction motor having the highest power factor at full load is

(a) shaded pole type.
(b) split-phase type.
(c) capacitor- start type.
(d) capacitor-run type. [GATE 2004]

78. In various types of split-phase 1-phase induction motors, the starting torques produced are in the following descending order

(a) Capacitor-split, resistor-split, shaded pole.
(b) Capacitor-split, shaded-pole, resistor split.
(c) Resistor-split, capacitor-split, shaded pole.
(d) Shaded pole, resistor-split, capacitor-split. [A.M.I.E. Sec B. Summer 2000]

79. Consider the following types of single phase motors:

1. Capacitor start induction motor.
2. Capacitor start and run induction motor.
3. Permanent split capacitor motor.
4. Shaded pole motor.

The correct sequence of these in the ascending order of magnitude of starting torque is
(a) 1-2-3-4.
(b) 2-3-4-1.
(c) 3-4-2-1.
(d) 4-3-2-1. [I.E.S. 2003]

80. Consider the following single-phase motors

I. Capacitor start motor
II. Capacitor start and run motor
III. Permanent split capacitor motor
IV. Shaded pole motor

The correct sequence of the increasing order of their cost is
(a) IV, III, II, I.
(b) IV, III, I, II.
(c) III, IV, II, I.
(d) III, IV, I, II.