Electrical Machine - I (3140913) MCQs

MCQs of DC Machines

Showing 11 to 20 out of 167 Questions
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11.
In a dc machine 72 number of coils are used. Find the number of commutator segments required?
(a) 18
(b) 36
(c) 54
(d) 72
Answer:

Option (d)

12.
In DC generators brushes are used for
(a) collecting of current without any sparkings
(b) collecting of voltage
(c) reduce eddy current loss
(d) convert ac armature current into dc
Answer:

Option (a)

13.
Which of the following type of brush and their application is/are correct?
(a) carbon brush → normal ratings
(b) electro graphite → large ratings
(c) copper graphite → low voltage high current density
(d) all of the above
Answer:

Option (d)

14.
Which of the following bearings and their uses are correct
(a) ball bearings → small machines
(b) roller bearings → large machines
(c) neither 1 nor 2
(d) both A and B
Answer:

Option (d)

15.
Which of the following windings are necessary in the case of all dc machines?
(a) closed winding
(b) lap winding
(c) wave winding
(d) open type winding
Answer:

Option (a)

16.
DC machine windings are
(a) full pitched
(b) short pitched
(c) either of these
(d) none of the above
Answer:

Option (a)

17.
Which of the following represents the commutator pitch?
(a) Number of conductors spanned by one coil at the back end of the armature
(b) Number of conductors spanned by one coil at the front end of the armature
(c) The distance between the staring of the first coil and its next successive coil
(d) Number of commutator segments between two successive coils
Answer:

Option (d)

18.
In a dc machine, 4 pole lap winding is used. The number of parallel paths is?
(a) 2
(b) 4
(c) 6
(d) 8
Answer:

Option (b)

19.
In a dc machine, 6 pole wave winding is used. The number of parallel paths is?
(a) 2
(b) 4
(c) 6
(d) 8
Answer:

Option (a)

20.
Inter pole winding is connected in-------------------------- ?
(a) series with armature
(b) series with main poles
(c) parallel with armature
(d) parallel with main poles
Answer:

Option (a)

Showing 11 to 20 out of 167 Questions
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