Electrical Machine - I (3140913) MCQs

MCQs of DC Machines

Showing 51 to 60 out of 167 Questions
3 4 5 6 7 8
51.
In DC machines shape of net flux density is?
(a) sine wave
(b) flat tapped or trapezoidal
(c) saddle shape
(d) peaky in nature
Answer:

Option (d)

52.
In DC machines internal characteristics are plotted between
(a) Eg vs IL
(b) Vt vs Ia
(c) Eg vs Ia
(d) Vt vs IL
Answer:

Option (c)

53.
Series generators are used in which of the following applications?
(a) Air crafts
(b) Arc welding
(c) Used as boosters in dc distribution or transmission
(d) All of the above
Answer:

Option (c)

54.
Which of the following generators are used in arc welding?
(a) shunt generators
(b) series generators
(c) cumulative compound generators
(d) differential compound generators
Answer:

Option (d)

55.
In which of the following generators negative voltage regulation can occur?
(a) shunt generator
(b) series generators
(c) over compound generator
(d) both B and C
Answer:

Option (d)

56.
A shunt generator is running at 1000 rpm. If the flux is reduced by half, then what is the new speed such that generated voltage remains the same?
(a) 0
(b) 500
(c) 1000
(d) 2000
Answer:

Option (d)

57.
A DC 4 pole lap wound generator is running at 1000 rpm having 1200 conductors and flux density is 10 mWb. find the generated emf?
(a) 200000
(b) 200
(c) 400
(d) 400000
Answer:

Option (b)

58.
Which motor cannot be started on no load?
(a) shunt motors
(b) series motors
(c) cumulative compound motors
(d) both B and C
Answer:

Option (b)

59.
Which of the following motors has negative speed regulation?
(a) Shunt motors
(b) Series motors
(c) Differential compound motors
(d) Both B and C
Answer:

Option (c)

60.
Field weakening control method is used for the _________ ?
(a) above rated speed
(b) below rated speed
(c) both A and B
(d) none of the above
Answer:

Option (a)

Showing 51 to 60 out of 167 Questions
3 4 5 6 7 8