electrical engineering MCQs – Page 302

Practise multiple-choice questions from electrical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

electrical engineering Mcqs

1. economics of power generation 2. analog electronics 3. solid state switching circuits 4. parallel circuits 5. switchgear and protection 6. op amp circuits 7. transistor audio power amplifiers 8. electrostatics 9. heating and welding 10. multi stage transistor amplifiers 11. passive filters 12. network theorems 13. regulated d c power supply 14. a c fundamentals circuits and circuit theory 15. electromagnetic induction 16. power electronics 17. magnetism and electromagnetism 18. transformers 19. modulation and demodulation 20. d c generators 21. semiconductor theory 22. single phase induction motors 23. semiconductor diode 24. hybrid parameters 25. digital electronics 26. oscillators 27. earthing or grounding 28. single stage transistor amplifiers 29. d c motors 30. transistor biasing 31. amplifiers with negative feedback 32. basic electrical 33. electronic instruments 34. synchronous motors 35. field effect transistors fet 36. magnetic circuit 37. control systems 38. industrial drives 39. power generation 40. series parallel circuits 41. transistor tuned amplifiers 42. electrical engineering materials 43. rectifiers and converters 44. integrated circuits 45. scr silicon controlled rectifiers 46. cables 47. polyphase induction motors 48. measurement and instrumentation 49. transistors 50. electrical machine design 51. electrolysis and storage of batteries 52. electric traction 53. transmission and distribution

6021. The torque angle, in a synchronous motor, is the angle between_______________?
0

A. magnetising current and back e.m.f.

B. the rotating stator flux and rotor poles

C. the supply voltage and the back e.m.f.

D. none of the above

6022. When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected______________?
0

A. it runs as a reluctance motor at the same speed

B. it runs as a reluctance motor at a lower speed

C. none of the above

D. the motor stops

6023. When load on an over-excited or under excited synchronous*motor is increased, rate of change of its armature current as compared with that of power factor is___________?
0

A. more

B. equal

C. twice

D. less

6024. A synchronous motor running with normal excitation adjusts to load increases essentially by increase in______________?
0

A. armature current

B. back e.m.f.

C. power factor

D. torque angle

6025. The maximum power developed in a synchronous motor occurs at a coupling angle of____________?
0

A. 180

B. 90

C. 30

D. 60

6026. The speed regulation of a synchronous motor is always___________?
0

A. 1%

B. zero

C. positive

D. 0.50%

6027. The size of a synchronous motor decreases with the increase in___________?
0

A. all of the above

B. flux density

C. speed

D. horse power rating

6028. In a synchronous motor, the damping winding is generally used to______________?
0

A. reduce noise level

B. provide starting torque only

C. none of the above

D. reduce the eddy currents

E. prevent hunting and provide the starting torque

6029. A synchronous motor is running on a load with normal excitation. Now if the load on the motor is increased
0

A. power factor as well as armature current will increase

B. power factor as well as armature current will decrease

C. power factor will increase but armature current will decrease

D. power factor will decrease and armature current will increase

6030. If one-phase of a 3-phase synchronous motor is short-circuited, motor will ______________?
0

A. will overheat in spots

B. will refuse to start

C. will not come upto speed

D. will fail to pull into step

6031. The ratio of starting torque to running torque in a synchronous motor is____________?
0

A. zero

B. infinity

C. one

D. two

6032. In a synchronous motor, the magnitude of stator back e.m.f. Eb depends on___________?
0

A. load on the motor

B. d.c. excitation only

C. both the speed and rotor flux

D. none of the above

6033. The speed of a synchronous motor:
0

A. decreases as the load decreases

B. none of the above

C. increases as the load increases

D. always remains constant

6034. A synchronous motor can be used as a synchronous capacitor when it is____________?
0

A. under-loaded

B. over-loaded

C. over-excited

D. under-excited

6035. The rotor copper losses, in a synchronous motor, are met by____________?
0

A. armature input

B. supply lines

C. motor input

D. d.c. source

6036. A three-phase synchronous motor will have_____________?
0

A. two slip-rings

B. three slip-rings

C. one slip-ring

D. no slip-rings

6037. The oscillations in a synchronous motor can be damped out by_______________?
0

A. oscillations cannot be damped

B. providing damper bars in the rotor pole faces

C. maintaining constant excitation

D. running the motor on leading power factors

6038. The standard full-load power factor ratings for synchronous motors are___________?
0

A. unity or zero

B. unity or 0.8 leading

C. zero or 0.8 leading

D. unity or 0.8 lagging

6039. The magnitude of field flux in a 3-phase synchronous motor?
0

A. varies with speed

B. varies with the load

C. remains constant at all loads

D. varies with power factor

6040. The effect of increasing the load on a synchronous motor running with normal excitation is to___________?
0

A. decrease both armature current and power factor

B. decrease armature current but increase power factor

C. increase armature current but decrease power factor

D. increase both its armature current and power factor

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