Top 150+ Solved DC Generators MCQ Questions Answer
Q. The demagnetising component of armature reaction in a D.C. generator
a. reduces generator e.m.f.
b. increases armature speed
c. reduces interpoles flux density
d. results in sparking trouble
Q. Magnetic field in a D.C. generator is produced by
a. electromagnets
b. permanent magnets
c. both (a) and (b)
d. none of the above
Q. The number of brushes in a commutator depends on
a. speed of armature
b. type of winding
c. voltage
d. amount of current to be collected
Q. Compensating windings are used in D.C. generators
a. mainly to reduce the eddy currents by providing local short-circuits
b. to provide path for the circulation of cooling air
c. to neutralise the cross-magnetising effect of the armature reaction
d. none of the above
Q. Which of the following components of a D.C, generator plays vital role for providingdirect current of a D.C. generator ?
a. Dummy coils
b. Commutator
c. Eye bolt
d. Equilizer rings
Q. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by
a. using conductor of annealed copper
b. using commutator with large number of segments
c. using carbon brushes of superior quality
d. using equiliser rings
Q. In D.C. generators, lap winding is used for
a. high voltage, high current
b. low voltage, high current
c. high voltage, low current
d. low voltage, low current
Q. The voltage drop for which of the following types of brush can be expected to be least ?
a. Graphite brushes
b. Carbon brushes
c. Metal graphite brushes
d. None of the above
Q. The armature core of a D.C. generator is usually made of
a. silicon steel
b. copper
c. non-ferrous material
d. cast-iron
Q. In D.C. generators, the brushes on commutator remain in contact with conductors which
a. lie under south pole
b. lie under north pole
c. lie under interpolar region
d. are farthest from the poles
Q. If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be
a. demagnetisation only
b. cross magnetisation as well as magnetisation
c. crossmagnetisation as well as demagnetising
d. cross magnetisation only
Q. D.C. generators are connected to the busbars or disconnected from them only underthe floating condition
a. to avoid sudden loading of the primemover
b. to avoid mechanicaljerk to the shaft
c. to avoid burning of switch contacts
d. all above
Q. Which of the following components of a D.C, generator plays vital role forproviding direct current of a D.C. generator ?
a. Dummy coils
b. Commutator
c. Eye bolt
d. Equilizer rings