electrical engineering MCQs – Page 301

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 Review each marked answer and report any item that may be outdated or unclear.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

6001. Under which of the following conditions hunting of synchronous motor is likely to occur?
0

A. Over-loading for long periods

B. Small and constant load

C. Periodic variation of load

D. Over-excitation

6002. Mostly, synchronous motors are of_____________?
0

A. induction type machines

B. smooth cylindrical type machines

C. salient pole type machines

D. alternator type machines

6003. In a synchronous motor running with fixed excitation, when the load is increased three times, its torque angle becomes approximately
0

A. six times

B. nine times

C. one-third

D. thrice

E. twice

6004. The back e.m.f. of a synchronous motor depends on______________?
0

A. all of the above

B. load

C. speed

D. load angle

6005. A 3-phase synchronous motor is running clockwise. If the direction of its field current is reversed
0

A. the motor continue to run in the same direction

B. the motor will run in the reverse direction

C. none of the above

D. the motor will stop

E. the winding of the motor will burn

6006. By which of the following methods the constant speed of a synchronous motor can be changed to new fixed value ?
0

A. By changing the supply frequency

B. By interchanging any two phases

C. By changing the applied voltage

D. By changing the load

6007. While starting a salient pole synchronous motor by induction motor action and connecting field discharge resistance across field, starting and accelerating torque is produced by_____________?
0

A. induction motor torque in field winding

B. induction motor torque in damper winding

C. eddy current and hysteresis torque in pole faces

D. reHetance motor torque due to saliency of the rotor

E. all of the above methods

6008. Synchronous motors are_____________?
0

A. none of the above

B. essentially self-starting

C. self-starting

D. not-self starting

6009. When the rotor speed, in a synchronous machine, becomes more than the synchronous speed during hunting, the damper bars develop_________________?
0

A. inductor motor torque

B. induction generator torque

C. synchronous motor torque

D. d.c. motor toque

E. none of the above

6010. In a synchronous motor, the maximum power developed depends on all of the following except:
0

A. supply voltage

B. maximum value of coupling angle

C. rotor excitation

D. direction of rotation

6011. The power developed by a synchronous motor will be maximum when the load angle is____________?
0

A. 120

B. 90

C. zero

D. 45

6012. Which of the following motors is non-self starting ?
0

A. D.C. series motor

B. Wound round induction motor

C. synchronous motor

D. Squirrel cage induction motor

6013. To limit the operating temperature an electrical machine should have proper____________?
0

A. current rating

B. power factor

C. voltage rating

D. speed

6014. . In a synchronous motor which loss varies with load ?
0

A. Copper loss

B. Bearing friction loss

C. Windage loss

D. Core loss

6015. Due to which of the following reasons a synchronous motor fails to pull into synchronism after applying D.C. field current?
0

A. High field current

B. Low field current

C. High core losses

D. Low short circuit ratio

6016. Which of the following losses is not dissipated by the stator core surface in a synchronous motor?
0

A. Iron losses in the stator

B. Windage losses

C. None of the above

D. Eddy current losses in the conductors

E. Copper losses in the slot portion of the conductors

6017. If the field of a synchronous motor is underexcited, the power factor will be_____________?
0

A. zero

B. leading

C. lagging

D. unity

6018. Which of the following losses, in a synchronous motor, does not vary with load?
0

A. None of the above

B. Any of the above

C. Windage loss

D. Copper losses

6019. A synchronous motor will always stop when:______________?
0

A. load in motor varies

B. supply voltage frequency changes

C. excitation winding gets disconnected

D. supply voltage fluctuates

6020. A synchronous motor is running with normal excitation. When the load is increased, the armature current drawn by it increases because
0

A. Er (net resultant voltage) in armature is increased

B. none of the above

C. power factor is decreased

D. Eb (back e.m.f.) becomes less than V (applied voltage)

E. speed of the motor is reduced

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