Top 150+ Solved Electrical Drives and Controls (EDC) MCQ Questions Answer
Q. For a dc machine, its commutator has a diameter of 50 c rotating at 1000 rpm. For a brush width of 1 cm, the time commutation taken by the machine will be
a. 0.382 ms
b. 0.456 ms
c. 0.573 ms
d. 0.312 ms
Q. An induction motor can be said analogous to
a. transformer
b. synchronous motor
c. universal motor
d. stepper motor
Q. A 3-phase induction motor with its rotor blocked behaves similar to a
a. transformer under short circuit of secondary terminals
b. transformer under open circuit of secondary
c. synchronous motor under slip test
d. synchronous motor under open circuit
Q. Why does DC motor sometimes run too fast when under-loaded?
a. due to weak field
b. due to high line voltage
c. due to brush-shifted to neutral
d. all of the mentioned
Q. Concentrated winding differ from distributed winding with the concern of
a. identical magnetic axis
b. two magnetic axis
c. no magnetic axis
d. physical spacing
Q. DC machines have windings and synchronous machines use windings.
a. closed,open
b. open, closed
c. open, open
d. closed, closed
Q. We can place closed windings in
a. ac commutator machine
b. stepper motor
c. ac machine
d. dc machine
Q. Which of the following machines can be used to place open slot winding?
a. ac machine
b. ac commutator machine, ac machine
c. dc machines
d. all of the mentioned
Q. The simplex lap winding has the range of winding pitch of
a. (-2,2)
b. (-1,1)
c. more than 2
d. less than 1
Q. Commutator segments in a DC shunt machine is equal to the number of
a. coil sides
b. turns
c. coils
d. slots
Q. We can employ dummy coils in a DC machine to
a. compensate reactance voltage
b. reduce armature reaction
c. provide mechanical balance to the armature
d. improve the waveforms generated inside the commutator
Q. In AC machines we should prefer double layer winding over single layer windings because
a. it requires identical coils
b. it is economical to use
c. it offers lower leakage reactance
d. all of the mentioned