DC Generator MCQ Multiple Choice Questions Answers - Page 3 for Practice
61. Eddy currents are induced in the pole shoes of a D.C. machine due to
Correct Answer is: relative rotation between field and armature
62. In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when
Correct Answer is: number of poles is 2
63. A D.C. generator can be considered as
Correct Answer is: rotating amplifier
64. The armature of D.C. generator is laminated to
Correct Answer is: reduce eddy current loss
65. The demagnetising component of armature reaction in a D.C. generator
Correct Answer is: reduces generator e.m.f.
66. If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to
Correct Answer is: reverse the field connections
67. Shunt generators are most suited for stable parallel operation because of their
Correct Answer is: drooping voltage characteristics
68. In D.C. generators the pole shoes are fastened to the pole core by
Correct Answer is: counter sunk screws
69. In any rotating machine that part which houses the conductors and in which e.m.f.induced is to be utilised is called
Correct Answer is: armature
70. In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be
Correct Answer is: 8
71. The essential condition for parallel operation of two D.C. generators is that they have
Correct Answer is: the same drooping voltage charac-teristics
72. Which of the following generating machine will offer constant voltage on all loads ?
Correct Answer is: Level compounded generator .
73. An exciter for a turbo generator is a
Correct Answer is: shunt generator
74. Following energized winding of a D.C. machine should not be opened as it wouldproduce high inductive voltage which may be dangerous to personnel and may cause itsown insulation failure.
Correct Answer is: Shunt field
75. Following D.C. generator will be in a position to build up without any residualmagnetism in the poles
Correct Answer is: self-excited generator
76. D.C. generator generally preferred for charging automobile batteries is
Correct Answer is: long shunt compound generator
77. Which of the following generator will have negligible terminal voltage while running onno-load ?
Correct Answer is: Series generator
78. Which of the following D.C. generators will be in a position to build up without anyresidual magnetism in the poles ?
Correct Answer is: None of the above
79. Which generator would you prefer for feeding long D.C. transmission lines ?
Correct Answer is: Over compound generator
80. In D.C. generators, the cause of rapid brush wear may be
Correct Answer is: any of the above
81. Which of the following generators will be preferred if they are required to be run inparallel ?
Correct Answer is: Shunt generators
82. In D.C. generators on no-load, the air gap flux distribution in space is
Correct Answer is: flat topped
83. For both lap and wave windings, there are as many commutator bars as the number of
Correct Answer is: winding elements
84. Iron losses in a D.C. machine are independent of variations in
Correct Answer is: load
85. Two D.C. shunt generators, each with armature resistance of 0.02 ohm and fieldresistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the loadcircuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be
Correct Answer is: 267.5 V
86. The number of brushes in a commutator depends on
Correct Answer is: amount of current to be collected
87. Two generators are running in parallel. One of the generators may run as motor forwhich of the following reasons ?
Correct Answer is: That generator takes large share of loads
88. The main factor which leads to unstable parallel operation of flat and over compounded generators is
Correct Answer is: their rising voltage characteristics
89. In a D.C. generator the magnetic neutral axis coincides with the geometrical neutralaxis, when
Correct Answer is: there is no load on|he generator
90. D.C. generators are connected to the busbars or disconnected from them only under thefloating condition
