DC Generator Objective Questions | MCQ Quiz for Practice

61. Eddy currents are induced in the pole shoes of a D.C. machine due to

1. oscillating magnetic field
2. pulsating magnetic flux
3. relative rotation between field and armature
4. all above

62. In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when

1. r.p.m. is more than 300
2. r.p.m. is less than 300
3. number of poles is 4
4. number of poles is 2

63. A D.C. generator can be considered as

1. rectifier
2. primemover
3. rotating amplifier
4. power pump

64. The armature of D.C. generator is laminated to

1. reduce the bulk
2. provide the bulk
3. insulate the core
4. reduce eddy current loss

65. The demagnetising component of armature reaction in a D.C. generator

1. reduces generator e.m.f.
2. increases armature speed
3. reduces interpoles flux density
4. results in sparking trouble

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

1. reverse the field connections
2. increase the field resistance
3. increase the speed of primemover
4. check armature insulation resis¬tance

67. Shunt generators are most suited for stable parallel operation because of their

1. rising voltage characteristics
2. identical voltage characteristics
3. drooping voltage characteristics
4. linear voltage characteristics

68. In D.C. generators the pole shoes are fastened to the pole core by

1. rivets
2. counter sunk screws
3. brazing
4. welding

69. In any rotating machine that part which houses the conductors and in which e.m.f.induced is to be utilised is called

1. rotor
2. stator
3. field
4. 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

1. 4
2. 8
3. 16
4. 32

71. The essential condition for parallel operation of two D.C. generators is that they have

1. same kW rating
2. the same operation r.p.m.
3. the same drooping voltage charac-teristics
4. same percentage regulation

72. Which of the following generating machine will offer constant voltage on all loads ?

1. Self-excited generator
2. Separately excited generator
3. Level compounded generator .
4. All of the above

73. An exciter for a turbo generator is a

1. separately excited generator
2. shunt generator
3. series generator
4. compound 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.

1. Series field
2. Compensating field
3. Inter pole field
4. Shunt field

75. Following D.C. generator will be in a position to build up without any residualmagnetism in the poles

1. series generator
2. shunt generator
3. compound generator
4. self-excited generator