Basic Electrical Engineering MCQ-14
Sikha
August 15, 2019
Basic Electrical Engineering MCQ-14
41. Which of the following statement about D.C. generators
is false ?
(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
Ans: d
42. 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
Ans: a
43. 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
Ans: a
44. 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
Ans: d
45. 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
Ans: c
46. Which of the following components of a D.C, generator
plays vital role for providing
direct current of a D.C. generator ?
(a) Dummy coils
(b) Commutator
(c) Eye bolt
(d) Equilizer rings
Ans: b
47. 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
Ans: c
48. 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
Ans: b
49. Two generators A and B have 6-poles each. Generator A
has wave wound armature
while generator B has lap wound armature. The ratio of the
induced e.m.f. is generator A
and B will be
(a)
2 : 3
(b) 3 : 1
(c) 3 : 2
(d) 1 : 3
Ans: b
50. 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
Ans: c
Basic Electrical Engineering MCQ-14
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Reviewed by Sikha
on
August 15, 2019
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