MCQOPTIONS
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MCQOPTIONS
This section includes 80 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.
| 1. |
Which of the following statements regarding single-phase induction motors correct? |
| A. | It requires only one winding |
| B. | It can rotate in one direction only |
| C. | It is self-starting |
| D. | It is not self-starting |
| Answer» E. | |
| 2. |
Which of the following statements regarding hysteresis motor is in incorrect? |
| A. | It is extremely sensitive to fluctuations in supply voltage |
| B. | Its high starting torque is due to its high rotor hysteresis loss |
| C. | It is extremely quiet in operation |
| D. | It accelerates from rest to full-speed almost instantaneously |
| Answer» B. Its high starting torque is due to its high rotor hysteresis loss | |
| 3. |
Which of the following single-phase induction motors is generally used in time phonographs ? |
| A. | Resistance start |
| B. | Capacitor start capacitor run |
| C. | Shaded pole |
| D. | Universal |
| Answer» D. Universal | |
| 4. |
Which of the following motors is used in tape-recorders ____________? |
| A. | Hysteresis motor |
| B. | Reluctance motor |
| C. | Capacitor-run motor |
| D. | Universal motor |
| Answer» B. Reluctance motor | |
| 5. |
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 |
| Answer» B. Capacitor run motor | |
| 6. |
When a D.C. series motor is connected to A.C. supply, the power factor will be low because of____________? |
| A. | high inductance of field and armature circuits |
| B. | induced current in rotor due to variations of flux |
| C. | fine copper wire winding |
| D. | none of the above |
| Answer» B. induced current in rotor due to variations of flux | |
| 7. |
Two-value capacitor motor finds increased application as compressor motor in small home air-conditioners because_____________? |
| A. | it is comparatively cheaper |
| B. | it has almost non-destructible capacitor |
| C. | it has low starting as well as running currents at relatively high power factor |
| D. | it is quiet in operation |
| Answer» D. it is quiet in operation | |
| 8. |
Torque developed by a single phase induction motor at starting is_____________? |
| A. | pulsating |
| B. | uniform |
| C. | none of the above |
| D. | nil |
| Answer» E. | |
| 9. |
To reverse the direction of rotation of acapacitor start motor while it is running we should___________? |
| A. | disconnect motor from the supply till it stops then reconnect it to supply with reversed connection of main or auxiliary winding |
| B. | disconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding |
| C. | reverse the direction of connection of the auxiliary winding and after motor comes to rest then connect auxiliary winding to the supply |
| D. | reverse the direction of connections of the auxiliary winding and immediately connect it to supply |
| Answer» B. disconnect motor from supply and immediately reconnect it to supply with reversed connections of the main winding | |
| 10. |
The wattage rating for a ceiling fan motor will be in the range_________? |
| A. | 200 to 250 W |
| B. | 250 to 500 W |
| C. | 50 to 150 W |
| D. | 10 to 20 W |
| Answer» D. 10 to 20 W | |
| 11. |
The wattage of motor for driving domestic sewing machine will be around__________? |
| A. | 100 to 150 W |
| B. | 40 to 75 W |
| C. | 10 to 30 W |
| D. | 5 to 10 W |
| Answer» B. 40 to 75 W | |
| 12. |
The value of starting capacitor of a fractional horse power motor will be__________? |
| A. | 100 uF |
| B. | 200 uF |
| C. | 300 uF |
| D. | 400 uF |
| Answer» D. 400 uF | |
| 13. |
The starting winding of a single-phase motor is placed in_________? |
| A. | armature |
| B. | field |
| C. | rotor |
| D. | stator |
| Answer» E. | |
| 14. |
The speed/load characteristics of a universal motor is same as that of_____________? |
| A. | A.C. motor |
| B. | D.C. shunt motor |
| C. | D.C. series motor |
| D. | none of the above |
| Answer» D. none of the above | |
| 15. |
The speed of a universal motor is usually reduced by using____________? |
| A. | gearing |
| B. | belts |
| C. | brakes |
| D. | chains |
| Answer» B. belts | |
| 16. |
The speed of a universal motor is generally reduced by using_________? |
| A. | gear trains |
| B. | V-belts |
| C. | brakes |
| D. | chains |
| Answer» B. V-belts | |
| 17. |
The speed control of universal motor used for sewing machines is by____________? |
| A. | friction |
| B. | varying the resistance |
| C. | tapping the field |
| D. | centrifugal mechanism |
| Answer» C. tapping the field | |
| 18. |
The shaded pole motor is used for__________? |
| A. | high starting torque |
| B. | low starting torque |
| C. | medium starting torque |
| D. | very high starting torque |
| Answer» C. medium starting torque | |
| 19. |
The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be___________? |
| A. | at the end connections |
| B. | at the end terminals |
| C. | anywhere on the winding inside a slot |
| D. | at the slot edge where coil enters or comes out of the slot |
| Answer» E. | |
| 20. |
The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it_____________? |
| A. | improves the efficiency |
| B. | helps the rotor teeth to remain under the stator teeth |
| C. | helps in reducing the tendency of the rotor teeth to remain under the stator teeth |
| D. | improves the power factor |
| Answer» D. improves the power factor | |
| 21. |
The rotor of a hysteresis motor is made of___________? |
| A. | aluminium |
| B. | cast iron |
| C. | chrome steel |
| D. | copper |
| Answer» D. copper | |
| 22. |
The rotor developed by a single-phase motor at starting is___________? |
| A. | more than i.he rated torque |
| B. | rated torque |
| C. | less than the rated torque |
| D. | zero |
| Answer» E. | |
| 23. |
The repulsion-start induction-run motor is used because of___________? |
| A. | good power factor |
| B. | high efficiency |
| C. | minimum cost |
| D. | high starting torque |
| Answer» E. | |
| 24. |
The range of efficiency for shaded pole motors is______________? |
| A. | 95% to 99% |
| B. | 80% to 90% |
| C. | 50% to 75% |
| D. | 5% to 35% |
| Answer» E. | |
| 25. |
The purpose of stator winding in the compensated repulsion motor is to_____________? |
| A. | provide mechanical balance |
| B. | improve power factor and provide better speed regulation |
| C. | prevent hunting in the motor |
| D. | eliminate armature reaction |
| Answer» C. prevent hunting in the motor | |
| 26. |
The power factor of a single-phase induction motor is usually? |
| A. | lagging |
| B. | always leading |
| C. | unity |
| D. | unity to 0.8 leading |
| Answer» B. always leading | |
| 27. |
The motor used on small lathes is usually_________? |
| A. | universal motor |
| B. | D.C. shunt motor |
| C. | single-phase capacitor run motor |
| D. | 3-phase synchronous motor |
| Answer» D. 3-phase synchronous motor | |
| 28. |
The motor used for the compressors is____________? |
| A. | d.c. series motor |
| B. | shaded pole motor |
| C. | capacitor-start capacitor-run motor |
| D. | reluctance motor |
| Answer» D. reluctance motor | |
| 29. |
The electric motor used in portable drills is__________? |
| A. | capacitor run motor |
| B. | hysteresis motor |
| C. | universal motor |
| D. | repulsion motor |
| Answer» D. repulsion motor | |
| 30. |
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 |
| Answer» C. retentivity of the rotor material | |
| 31. |
The direction of rotation of universal motor can be reversed the by reversing the flow of current through__________? |
| A. | armature winding |
| B. | field winding |
| C. | either armature winding or field winding |
| D. | none of the above |
| Answer» D. none of the above | |
| 32. |
The capacitors used in single-phase capacitor motors have no__________? |
| A. | voltage rating |
| B. | dielectric medium |
| C. | polarity marking |
| D. | definite value |
| Answer» D. definite value | |
| 33. |
n a split phase motor, the running winding should have? |
| A. | high resistance and low inductance |
| B. | low resistance and high inductance |
| C. | high resistance as well as high inductance |
| D. | low resistance as well as low inductiance |
| Answer» C. high resistance as well as high inductance | |
| 34. |
Most of the fractional horsepower motors have either___________? |
| A. | hard and annealed bearings |
| B. | ball or roller bearings |
| C. | soft and porous bearings |
| D. | plain or sleeve bearings |
| Answer» E. | |
| 35. |
Locked rotor current of a shaded pole motor is____________? |
| A. | equal to full load current |
| B. | less than full load current |
| C. | slightly more than full load current |
| D. | several times the full load current |
| Answer» D. several times the full load current | |
| 36. |
In split phase motor main winding is of _____________? |
| A. | thin wire placed at the top of the slots |
| B. | thin wire placed at the bottom of the slots |
| C. | thick wire placed at the bottom of the slots |
| D. | thick wire placed at the top of the” slots |
| Answer» D. thick wire placed at the top of the” slots | |
| 37. |
In split-phase motor auxiliary winding is of___________? |
| A. | thick wire placed at the bottom of the slots |
| B. | thick wire placed at the top of the slots |
| C. | thin wire placed at the top of the slots |
| D. | thin wire placed at the bottom of the slots |
| Answer» D. thin wire placed at the bottom of the slots | |
| 38. |
In repulsion motor, zero torque is developed when___________? |
| A. | brush axis is 45° electrical to field axis |
| B. | brush axis coincides with the field axis |
| C. | brush axis is 90° electrical to field axis |
| D. | both B. and (c) |
| Answer» E. | |
| 39. |
In repulsion motor direction of rotation of motor____________? |
| A. | is opposite to that of brush shift |
| B. | is the same as that of brush shift |
| C. | is independent of brush shift |
| Answer» C. is independent of brush shift | |
| 40. |
In repulsion motor, maximum torque is developed when____________? |
| A. | brush axis is at 45° electrical to the field axis |
| B. | brush axis coincides with the field axis |
| C. | brush axis is at 90° electrical to the field axis |
| D. | none of the above |
| Answer» B. brush axis coincides with the field axis | |
| 41. |
In case of high speed universal motor which of the following needs more attention? |
| A. | End play |
| B. | Air gap |
| C. | Insulation in rotor |
| D. | Balancing of rotor |
| Answer» E. | |
| 42. |
In case of a shaded pole motor the direction of rotation of the motor is__________? |
| A. | from main pole to shaded pole |
| B. | from shaded pole to main pole |
| C. | either of the above depending on voltage |
| D. | either of the above depending on power factor |
| Answer» B. from shaded pole to main pole | |
| 43. |
In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will_____________? |
| A. | become unstable |
| B. | draw excessive armature current and may burn out |
| C. | fall out of synchronism and come to stand still |
| D. | run as induction motor |
| Answer» E. | |
| 44. |
In capacitor start single-phase motors____________? |
| A. | current in the starting winding leads the voltage |
| B. | current in the starting winding lags the voltage |
| C. | current in the starting winding is in phase with voltage in running winding |
| D. | none of the above |
| Answer» B. current in the starting winding lags the voltage | |
| 45. |
In A.C. series motor compensating winding is employed to_____________? |
| A. | reduce the effects of armature reaction |
| B. | increase the torque |
| C. | reduce sparking at the brushes |
| D. | none of the above |
| Answer» D. none of the above | |
| 46. |
In a universal motor, the most common cause of brush sparking is___________? |
| A. | open armature winding |
| B. | shorted armature winding |
| C. | shorted field winding |
| D. | high commutator mica |
| E. | all of the above |
| Answer» F. | |
| 47. |
In a two value capacitor motor, the capacitor used for running purposes is_______________? |
| A. | air capacitor |
| B. | paper spaced oil filled type |
| C. | ceramic type |
| D. | a.c. electrolytic type |
| Answer» C. ceramic type | |
| 48. |
In a split phase motor____________? |
| A. | the starting winding is connected through a centrifugal switch |
| B. | the running winding is connected through a centrifugal switch |
| C. | both starting and running windings are connected through a centrifugal switch |
| D. | centrifugal switch is used to control supply voltage |
| Answer» B. the running winding is connected through a centrifugal switch | |
| 49. |
In a single phase motor the centrifugal switch____________? |
| A. | disconnects auxiliary winding of the motor |
| B. | disconnects main winding of the motor |
| C. | reconnects the main winding the motor |
| D. | reconnects the main winding the motor |
| Answer» B. disconnects main winding of the motor | |
| 50. |
In a shaded pole single-phase motor, the revolving field is produced by the use of_________? |
| A. | inductor |
| B. | capacitor |
| C. | resistor |
| D. | shading coils |
| Answer» E. | |