1) A D.C. generator can be considered as____________? a. rectifier b. primemover c. rotating amplifier d. power pump
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2) The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be_______________? a. E/2 b. 2E c. slightly less than E d. E
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3) In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilized is called____________? a. rotor b. stator c. field d. armature
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4) The armature core of a D.C. generator is usually made of__________________? a. silicon steel b. copper c. non-ferrous material d. cast-iron
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5) In a D.C. machine stray loss is the sum of_____________? a. total copper loss and mechanical loss b. armature copper loss and iron loss c. shunt field copper loss and mechanical loss d. iron loss and mechanical loss
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6) Satisfactory commutation of D.C. machines requires______________? a. brushes should be of proper grade and size b. brushes should smoothly run in the holders c. smooth, concentric commutator properly undercut d. all of the above
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7) Lap winding is composed of_____________? a. any even number of conductors b. any odd number of conductors c. that even number which is exact multiple of poles + 2 d. that even number which is exact multiple of poles
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8) Open circuited armature coil of a D.C. machine is________________? a. identified by the scarring of the commutator segment to which open circuited coil is connected b. indicated by a spark completely around the commutator c. both A. and (b) d. none of the above
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9) For the parallel operation of two or more D.C. compound generators, we should ensure that_______________? a. voltage of the incoming generator should be same as that of bus bar b. polarity of incoming generator should be same as that of bus bar c. all the series fields should be run in parallel by means of equilizer connection d. series fields of all generators should be either on positive side or negative side of the armature e. all conditions mentioned above should be satisfied
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10) In a D.C. generator in case the resistance of the field winding is increased, then output voltage will____________? a. increase b. decrease c. remain unaffected d. fluctuate heavily
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11) D.C. series generator is used_________________? a. to supply traction load b. to supply industrial load at constant voltage c. voltage at the toad end of the feeder d. for none of the above purpose
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12) An exciter for a turbo generator is a_____________? a. separately excited generator b. shunt generator c. series generator d. compound generator
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13) Following D.C. generator will be in a position to build up without any residual magnetism in the poles______________? a. series generator b. shunt generator c. compound generator d. self-excited generator
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14) Interpole flux should be sufficient to_____________? a. neutralise the commutating self induced e.m.f. b. neutralise the armature reaction flux c. neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil d. perform none of the above functions
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15) In case of a flat compounded generator: a. voltage generated is less than the rated voltage b. generated voltage is proportional to the load on the generator c. voltage remains constant irrespective of the load d. speed varies in proportion to the load on the generator
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16) D.C. generator generally preferred for charging automobile batteries is______________? a. series generator b. shunt generator c. long shunt compound generator d. any of’the above
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17) In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when____________? a. r.p.m. is more than 300 b. r.p.m. is less than 300 c. number of poles is 4 d. number of poles is 2
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18) Which of the following generator will have negligible terminal voltage while running on no-load? a. Series generator b. Shunt generator c. Compound generator d. Separately excited generator
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19) Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles? a. Series generator b. Shunt generator c. Compound generator d. None of the above
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20) Permeance is the reciprocal of______________? a. flux density b. reluctance c. ampere-turns d. resistance
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