electrical engineering MCQs – Page 298

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 Review each marked answer and report any item that may be outdated or unclear.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

5941. A pony motor is basically a_________?
0

A. D.C. shunt motor

B. small induction motor

C. D.C. series motor

D. double winding A.C./D.C. motor

5942. When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor___________?
0

A. tends to becomes zero

B. remains same as the original value

C. decreases to half the original value

D. increases to two times the original value

5943. The minimum armature current of the synchronous motor corresponds to operation at______________?
0

A. 0.707 power factor leading

B. unity power factor

C. zero power factor leading

D. 0.707 power factor lagging

5944. Slip rings are usually made of__________?
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A. copper or aluminium

B. silver or gold

C. carbon or graphite

D. brass or steel

5945. Synchronous motors are generally not self-starting because:
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A. starting winding is not provided on the machines

B. the direction of rotation is not fixed

C. startes cannot be used on these machines

D. the direction of instantaneous torque reverses after half cycle

5946. The power factor of a synchronous motor is better than that of induction motor because
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A. synchronous motor runs at synchronous speed

B. stator supply is relieved of responsibility of producing magnetic field

C. synchronous motor has large air gap

D. mechanical load on the motor can be adjusted

5947. When the field of a synchronous motor is under-excited, the power factor will be____________?
0

A. zero

B. leading

C. lagging

D. unity

5948. Riunting in a synchronous motor takes place___________?
0

A. motor is under loaded

B. when load varies

C. when power factor is unity

D. when supply voltage fluctuates

5949. In a synchronous motor, the magnitude of stator back e.m.f. & depends on_______________?
0

A. d.c. excitation only

B. speed of the motor

C. load on the motor

D. both the speed and rotor flux

5950. Change of D.C. excitation of a synchronous motor changes:
0

A. applied voltage of the motor

B. all of the these

C. none of the these

D. motor speed

E. power factor of power drawn by the motor

5951. A synchronous motor can operate at____________?
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A. unity power factor only

B. leading power factor only

C. lagging, leading and unity power factors

D. lagging power factor only

5952. In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then
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A. the motor is said to be fully loaded

B. the excitation is said to be hundred per cent

C. the excitation is said to be zero per cent

D. the torque generated is maximum

5953. Armature of a synchronous machine is____________?
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A. armature is associated with large power as compared to the field circuits

B. of difficulty of providing high voltage insulation on rotor

C. of reducing number of slip rings on the rotor

D. all of the above reasons

5954. The percentage slip in case of a synchronous motor is____________?
0

A. 1%

B. zero

C. 0.50%

D. 100%

5955. The duration of sudden snort-circuit test on a synchronous motor is usually about_____________?
0

A. one hour

B. none of the above

C. one second

D. one minute

5956. A synchronous motor installed at the receiving end substation operates with such an excitation that it takes power at lagging power factor. Now if the applied voltage of the synchronous motor goes down, the power factor of the synchronous motor will___________?
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A. none of the above

B. go down

C. improve

D. remain same

5957. If load (or torque) angle of a 4-pole synchronous motor is 6 electrical, its value in mechanical degrees is__________?
0

A. 6

B. 4

C. 2

D. 3

5958. In a synchronous motor, V-curves represent relation between____________?
0

A. armature current and field current

B. field current and speed

C. field current and power factor

D. power factor and speed

5959. A synchronous machine with large air gap has______________?
0

A. a higher synchronizing power which makes the machine less sensitive to load variations

B. a small value of inherent regulation

C. a higher value of stability limit

D. all of the above

5960. A rotory converter can also be run as a___________?
0

A. induction motor

B. d.c. compound motor

C. d.c. series motor

D. d.c. shunt motor

E. synchronous motor

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