electrical engineering MCQs – Page 38

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 Review each marked answer and report any item that may be outdated or unclear.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

741. An exciter for a turbo generator is a_____________?
0

A. compound generator

B. series generator

C. shunt generator

D. separately excited generator

742. In a D.C. generator:___________________?
0

A. external characteristic = magnetisation characteristic ohmic drop armature reaction

B. internal characteristic = magnetisation characteristic ohmic drop

C. external resistance = internal char-acteristic armature reaction

D. magnetisation characteristic = external characteristic

743. As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit____________________?
0

A. a resistance is connected in series with armature

B. a resistance is connected parallel to the armature

C. armature is temporarily open circuited

D. a high value resistor is connected across the field winding

744. The armature voltage control of D.C. motor provides_____________?
0

A. constant current drive

B. constant voltage drive

C. none of the above

D. constant torque drive

745. Compensating windings are used in D.C. generators______________?
0

A. none of the above

B. to neutralise the cross-magnetising effect of the armature reaction

C. mainly to reduce the eddy currents by providing local short-circuits

D. to provide path for the circulation of cooling air

746. The critical resistance of the D.C. generator is the resistance of_____________?
0

A. load

B. brushes

C. armature

D. field

747. The e.m.f. generated in a D.C. generator is directly proportional to____________?
0

A. flux/pole

B. speed of armature

C. number of poles

D. all of the above

748. Satisfactory commutation of D.C. machines requires______________?
0

A. brushes should be of proper grade and size

B. smooth, concentric commutator properly undercut

C. brushes should smoothly run in the holders

D. all of the above

749. When two D.C. series motors are connected in parallel, the resultant speed is____________?
0

A. zero

B. loss than the normal speed

C. normal speed

D. more than the normal speed

750. As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately______________?
0

A. 10 percent

B. 25 percent

C. 40 percent

D. 5 percent

751. The speed of a D.C. shunt motor can be increased by_______________?
0

A. reducing the resistance in the armature circuit

B. reducing the resistance in the field circuit

C. increasing the resistance in armature circuit

D. increasing the resistance in field circuit

752. Which of the following test can be performed on DC series motor?
0

A. Brake test

B. Swinburne test

C. Field test

D. Hopkinson test

753. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be_____________?
0

A. under compounded

B. level compounded

C. cumulatively compounded

D. differentially compounded

754. The ratio of starting torque to full-load torque is least in case of____________?
0

A. compound motors

B. none of the above

C. shunt motors

D. series motors

755. Which D.C. motor will be preferred for machine tools ?
0

A. Differential compound motor

B. Cumulative compound motor

C. Series motor

D. Shunt motor

756. When two D.C. series generators are running in parallel, an equilizer bar is used________________?
0

A. to increase the speed and hence generated e.m.f.

B. to increase the series flux

C. so that two similar machines will pass approximately equal currents to the load

D. to reduce the combined effect of ar-mature reaction of both machines

757. During rheostat braking of D.C. series motors_____________?
0

A. motor is run as a generator

B. motor is run at reduced speed

C. motor is reversed in direction

758. The voltage drop for which of the following types of brush can be expected to be least ?
0

A. None of the above

B. Metal graphite brushes

C. Graphite brushes

D. Carbon brushes

759. For the same H.P. rating and full load speed, following motor has poor starting torque_____________?
0

A. shunt

B. cumulativelycompounded

C. series

D. differentially compounded

760. In a D.C. generator the critical resistance refers to the resistance of_____________?
0

A. field

B. brushes

C. load

D. armature

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