electrical engineering MCQs – Page 282

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 Review each marked answer and report any item that may be outdated or unclear.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

5621. If a D.C. motor designed for 40C ambient temperature is to be used for 50C ambient temperature, then the motor_____________?
0

A. is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor

B. can be used for 50C ambient temperature also

C. of higher H.P. should be selected

D. of lower H.P. should be selected

5622. In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be_____________?
0

A. more than full-load current

B. less than full-load current

C. almost negligible

D. rated full-load current

5623. Which of the following tests will be suitable for testing two similar D.C. series motors of large capacity ?
0

A. Hopkinsons test

B. Brake test

C. Swinburnes test

D. Field test

5624. The total losses in a well designed D.C. generator of 10 kW will be nearly______________?
0

A. 500 W

B. 1000 W

C. 1500 W

D. 100 W

5625. Which of the following motor is preferred for operation in highly explosive atmosphere ?
0

A. Series motor

B. Shunt motor

C. Air motor

D. Battery operated motor

5626. Which of the following motors is usually used in house-hold refrigerators ?
0

A. Reluctance motor

B. D.C. series motor

C. D.C. shunt motor

D. Single phase induction motor (split phase start or induction run motor)

E. Synchronous motor

5627. Speed control by Ward Leonard method gives uniform speed variation_____________?
0

A. in one direction

B. in both directions

C. below normal speed only

D. above normal speed only

5628. In Ward-Leonard control the lower limit of speed is imposed by________?
0

A. mechanical losses of motor and generator together

B. residual magnetism of the generator

C. all of the above

D. core losses of motor

5629. Which of the following load normally needs starting torque more than the rated torque?
0

A. Air compressors

B. Centrifugal pumps

C. Conveyors

D. Blowers

5630. In a D.C. generator, the iron losses mainly take place in___________/
0

A. armature conductors

B. armature rotor

C. commutator

D. yoke

5631. The speed of a D.C. shunt motor more than its full-load speed can be obtained by_____________?
0

A. increasing the field current

B. increasing the armature current

C. decreasing the field current

D. decreasing the armature current

5632. Which motor has the poorest speed control?
0

A. Differentially compounded motor

B. Cumulatively compounded motor

C. Shunt motor

D. Series motor

5633. With the increase in temperature, the speed of DC series motor______________?
0

A. decreases

B. remain same

C. none of the above

D. increases

5634. Armature reaction in dc motor results___________?
0

A. open circuit

B. decrease in speed

C. short circuit

D. increase in speed

5635. Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ?
0

A. Using non-magnetic material for frame

B. Using material of low hysteresis co-efficient for armature core material

C. Providing laminations in stator

D. Providing laminations in armature core

5636. For a D.C. shunt motor if the excitation is changed_______________?
0

A. torque will remain constant

B. torque will change but power will remain constant

C. torque and power both will change

D. torque, power and speed, all will change

5637. The current drawn by the armature of D.C. motor is directly proportional to__________?
0

A. the voltage across the terminals

B. the torque required

C. the speed of the motor

D. none of the above

5638. If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens__________?
0

A. this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses D. motor will run at very slow speed

B. this will make armature to take heavy current, possibly burning it

C. nothing will happen to the motor

5639. A direct on line starter is used: for starting motors___________?
0

A. up to 20 H.P

B. up to 15 H.P

C. up to 5 H.P

D. up to 10 H.P

5640. In the D.C. motor the iron losses occur in____________?
0

A. the brushes

B. the armature

C. the field

D. the commutator

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