electrical engineering MCQs – Page 259

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 Review each marked answer and report any item that may be outdated or unclear.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 generation2. analog electronics3. solid state switching circuits4. parallel circuits5. switchgear and protection6. op amp circuits7. transistor audio power amplifiers8. electrostatics9. heating and welding10. multi stage transistor amplifiers11. passive filters12. network theorems13. regulated d c power supply14. a c fundamentals circuits and circuit theory15. electromagnetic induction16. power electronics17. magnetism and electromagnetism18. transformers19. modulation and demodulation20. d c generators21. semiconductor theory22. single phase induction motors23. semiconductor diode24. hybrid parameters25. digital electronics26. oscillators27. earthing or grounding28. single stage transistor amplifiers29. d c motors30. transistor biasing31. amplifiers with negative feedback32. basic electrical33. electronic instruments34. synchronous motors35. field effect transistors fet36. magnetic circuit37. control systems38. industrial drives39. power generation40. series parallel circuits41. transistor tuned amplifiers42. electrical engineering materials43. rectifiers and converters44. integrated circuits45. scr silicon controlled rectifiers46. cables47. polyphase induction motors48. measurement and instrumentation49. transistors50. electrical machine design51. electrolysis and storage of batteries52. electric traction53. transmission and distribution
5161. In a D.C. machine stray loss is the sum of_____________?
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A. armature copper loss and iron loss

B. total copper loss and mechanical loss

C. shunt field copper loss and mechanical loss

D. iron loss and mechanical loss
5162. The resistance of armature winding depends on
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A. length of conductor

B. number of conductors

C. all of the above

D. cross-sectional area of the conductor

5163. In the case of lap winding resultant pitch is____________?
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A. division of front pitch by back pitch

B. difference of front and back pitches

C. multiplication of front and back pitches

D. sum of front and back pitches

5164. Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator ?
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A. Commutator

B. Dummy coils

C. Eye bolt

D. Equilizer rings

5165. In D.C. generators the pole shoes are fastened to the pole core by_____________?
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A. rivets

B. welding

C. brazing

D. counter sunk screws
5166. Compensating windings are used in D.C. generators______________?
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A. to neutralise the cross-magnetising effect of the armature reaction

B. none of the above

C. to provide path for the circulation of cooling air

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

5167. D.C. series generator is used_________________?
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A. to supply industrial load at constant voltage

B. to supply traction load

C. voltage at the toad end of the feeder

D. for none of the above purpose

5168. In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except______________?
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A. compensating winding

B. shifting of axis of brushes

C. dummy coils

D. interpoles

5169. In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when____________?
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A. r.p.m. is less than 300

B. number of poles is 2

C. number of poles is 4

D. r.p.m. is more than 300

5170. Which of the following generating machine will offer constant voltage on all loads?
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A. Level compounded generator

B. All of the above

C. Separately excited generator

D. Self-excited generator

5171. The voltage drop for which of the following types of brush can be expected to be least ?
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A. Graphite brushes

B. None of the above

C. Carbon brushes

D. Metal graphite brushes
5172. An exciter for a turbo generator is a_____________?
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A. series generator

B. separately excited generator

C. compound generator

D. shunt generator
5173. Welding generator will have____________?
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A. delta winding

B. wave winding

C. lap winding

D. duplex wave winding

5174. The bearings used to support the rotor shafts are generally______________?
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A. magnetic bearmgs

B. needle bearings

C. ball bearings

D. bush bearings

5175. The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except:_____________?
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A. armature reaction

B. commutation

C. armature resistance drop

D. field weakening due to armature reaction and armature

5176. In a four-pole D.C. machine____________?
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A. two north poles follow two south poles

B. all the four poles are south poles

C. alternate poles are north and south

D. all the four poles are north poles

5177. The insulating material used between the commutator segments is normally_____________?
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A. mica

B. paper

C. insulating varnish

D. graphite

5178. Which of the following statement about D.C. generators is false ?
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A. Compensating winding in a D.C. machine helps in commutation

B. In a D. C. generator interpoles winding is connected in series with the armature winding

C. Back pitch and front pitch are both odd and approximately equal to the pole pitch

D. Equilizing bus bars are used with parallel running of D.C. shunt generators
5179. The rapid wear of brushes takes place due to____________?
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A. all of the above factors

B. high mica insulation between com-mutation bars

C. excessive spring pressure

D. abrasion from dust

E. rough commutator bars

5180. In D.C. generators, the cause of rapid brush wear may be___________?
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A. any of the above

B. imperfect contact

C. severe sparking

D. rough commutator surface