MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 82 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
In the circle diagram for induction motor, the diameter of the circle represents____________? |
| A. | slip |
| B. | rotor current |
| C. | running torque |
| D. | line voltage |
| Answer» C. running torque | |
| 52. |
In squirrel cage induction motors, the rotor slots are usually given slight skew in order to__________? |
| A. | reduce windage losses |
| B. | reduce eddy currents |
| C. | reduce accumulation of dirt and dust |
| D. | reduce magnetic hum |
| Answer» E. | |
| 53. |
In Ns is the synchronous speed and s the slip, then actual running speed of an induction motor will be___________? |
| A. | Ns |
| B. | s.N, |
| C. | (l-s)Ns |
| D. | (Ns-l)s |
| Answer» D. (Ns-l)s | |
| 54. |
In medium sized induction motors, the slip is generally around___________? |
| A. | 0.04% |
| B. | 0.4% |
| C. | 4% |
| D. | 14% |
| Answer» D. 14% | |
| 55. |
In induction motor, percentage slip depends on__________? |
| A. | supply frequency |
| B. | supply voltage |
| C. | copper losses in motor |
| D. | none of the above |
| Answer» D. none of the above | |
| 56. |
In case the air gap in an induction motor is increased? |
| A. | the magnetising current of the rotor will decrease |
| B. | the power factor will decrease |
| C. | speed of motor will increase |
| D. | the windage losses will increase |
| Answer» C. speed of motor will increase | |
| 57. |
In case the air gap in an induction motor is increased____________? |
| A. | the magnetising current of the rotor will decrease |
| B. | the power factor will decrease |
| C. | speed of motor will increase |
| D. | the windage losses will increase |
| Answer» C. speed of motor will increase | |
| 58. |
In case of the induction motors the torque is___________? |
| A. | inversely proportional to (Vslip) |
| B. | directly proportional to (slip)2 |
| C. | inversely proportional to slip |
| D. | directly proportional to slip |
| Answer» E. | |
| 59. |
In case of a double cage induction motor, the inner cage has__________? |
| A. | high inductance arid low resistance |
| B. | low inductance and high resistance |
| C. | low inductance and low resistance |
| D. | high inductance and high resistance |
| Answer» B. low inductance and high resistance | |
| 60. |
In case of 3-phase induction motors, plugging means__________? |
| A. | pulling the motor directly on line without a starter |
| B. | locking of rotor due to harmonics |
| C. | starting the motor on load which is more than the rated load |
| D. | interchanging two supply phases for quick stopping |
| Answer» E. | |
| 61. |
In an induction motor the relationship between stator slots and rotor slots is that_____________? |
| A. | stator slots are equal to rotor slots |
| B. | stator slots are exact multiple of rotor slots |
| C. | stator slots are not exact multiple of rotor slots |
| D. | none of the above |
| Answer» D. none of the above | |
| 62. |
In an induction motor, no-load the slip is generally____________? |
| A. | less than 1% |
| B. | 1.5% |
| C. | 2% |
| D. | 4% |
| Answer» B. 1.5% | |
| 63. |
In an induction motor if air-gap is increased__________? |
| A. | the power factor will be low |
| B. | windage losses will be more |
| C. | bearing friction will reduce |
| D. | copper loss will reduce In an induction motor |
| Answer» B. windage losses will be more | |
| 64. |
In a three-phase induction motor_______________? |
| A. | iron losses in stator will be negligible as compared to that in rotor |
| B. | iron losses in motor will be neg¬ligible as compared to that in rotor |
| C. | iron losses in stator will be less than that in rotor |
| D. | iron losses in stator will be more than that in rotor |
| Answer» E. | |
| 65. |
In a three-phase induction motor__________? |
| A. | power factor at starting is high as compared to that while running |
| B. | power factor at starting is low as compared to that while running |
| C. | power factor at starting in the same as that while running |
| Answer» C. power factor at starting in the same as that while running | |
| 66. |
In a three-phase induction motor, the number of poles in the rotor winding is always__________? |
| A. | zero |
| B. | more than the number of poles in stator |
| C. | less than number of poles in stator |
| D. | equal to number of poles in stator |
| Answer» E. | |
| 67. |
In a star-delta starter of an induction motor___________? |
| A. | resistance is inserted in the stator |
| B. | reduced voltage is applied to the stator |
| C. | resistance is inserted in the rotor |
| D. | applied voltage perl stator phase is 57.7% of the line voltage |
| Answer» E. | |
| 68. |
In a squirrel cage motor the induced e.m.f. is___________? |
| A. | dependent on the shaft loading |
| B. | dependent on the number of slots |
| C. | slip times the stand still e.m.f. induced in the rotor |
| D. | none of the above |
| Answer» D. none of the above | |
| 69. |
If any two phases for an induction motor are interchanged_______? |
| A. | the motor will run in reverse direction |
| B. | the motor will run at reduced speed |
| C. | the motor will not run |
| D. | the motor will burn |
| Answer» B. the motor will run at reduced speed | |
| 70. |
If an induction motor with certain ratio of rotor to stator slots, runs at 1/7 of the normal speed, the phenomenon will be termed as____________? |
| A. | humming |
| B. | hunting |
| C. | crawling |
| D. | cogging |
| Answer» D. cogging | |
| 71. |
If a 3-phase supply is given to the stator and rotor is short circuited rotor will move___________? |
| A. | in the opposite direction as the direction of the rotating field |
| B. | in the same direction as the direction of the field |
| C. | in any direction depending upon phase squence of supply |
| Answer» C. in any direction depending upon phase squence of supply | |
| 72. |
For driving high inertia loads best type of induction motor suggested is_____________? |
| A. | slip ring type |
| B. | squirrel cage type |
| C. | any of the above |
| D. | none of the above |
| Answer» B. squirrel cage type | |
| 73. |
DOL starting of induction motors is usually restricted to_____________? |
| A. | low horsepower motors |
| B. | variable speed motors |
| C. | high horsepower motors |
| D. | high speed motors |
| Answer» B. variable speed motors | |
| 74. |
Blocked rotor test on induction motors is used to find out? |
| A. | leakage reactance |
| B. | power factor on short circuit |
| C. | short-circuit current under rated voltage |
| D. | all of the above |
| Answer» E. | |
| 75. |
As load on an induction motor goes on increasing______________? |
| A. | its power factor goes on decreasing |
| B. | its power factor remains constant |
| C. | its power factor goes on increasing even after full load |
| D. | its power factor goes on increasing up to full load and then it falls again |
| Answer» E. | |
| 76. |
An induction motor with 1000 r.p.m. speed will have____________? |
| A. | 8 poles |
| B. | 6 poles |
| C. | 4 poles |
| D. | 2 poles |
| Answer» C. 4 poles | |
| 77. |
An induction motor is__________? |
| A. | self-starting with zero torque |
| B. | self-starting with high torque |
| C. | self-starting with low torque |
| D. | non-self starting |
| Answer» D. non-self starting | |
| 78. |
An induction motor is identical to_________? |
| A. | D.C. compound motor |
| B. | D.C. series motor |
| C. | synchronous motor |
| D. | asynchronous motor |
| Answer» E. | |
| 79. |
An induction motor can run at synchronous speed when____________? |
| A. | it is run on load |
| B. | it is run in reverse direction |
| C. | it is run on voltage higher than the rated voltage |
| D. | e.m.f. is injected in the rotor circuit |
| Answer» E. | |
| 80. |
A squirrel cage induction motor is not selected when___________? |
| A. | initial cost is the main consideration |
| B. | maintenance cost is to be kept low |
| C. | higher starting torque is the main consideration |
| D. | all above considerations are involved |
| Answer» D. all above considerations are involved | |
| 81. |
A pump induction motor is switched on to a supply 30% lower than its rated voltage. The pump runs. What will eventually happen ? It will____________? |
| A. | stall after sometime |
| B. | stall immediately |
| C. | continue to run at lower speed without damage |
| D. | get heated and subsequently get damaged |
| Answer» E. | |
| 82. |
A double squirrel-cage induction motor has______________? |
| A. | two rotors moving in oppsite direction |
| B. | two parallel windings in stator |
| C. | two parallel windings in rotor |
| D. | two series windings in stator |
| Answer» D. two series windings in stator | |