Top 150+ Solved Electrical Drives and Controls (EDC) MCQ Questions Answer
Q. The effect of fringing increases as we
a. increase air gap
b. decrease air gap
c. increase in flux density
d. introduce more ferric core material
Q. If the students give a forward shift of 10° to the dc generator, then it
a. reduces flux per pole
b. improves flux per pole
c. increases the flux density in core
d. none of the mentioned
Q. A dc machine is run at rated speed in forward direction and then in backward direction. It is observed that, speeds of the rotation are different, then it leads to the conclusion of
a. incorrect brush placement
b. incorrect pole and core alignment
c. incorrect field supply
d. all of the mentioned
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. The torque limit of speed for a shunt motor
a. remains constant till base speed
b. remains constant after base speed
c. varies linearly after base speed
d. varies inversely till base speed
Q. A laboratory group was working with a set of 3-hp shunt DC motor. But there was a mistake that it was fused with a 0.3A fuse instead 3A fuse. Then it was started
a. a flash occurred instantly
b. it ran for 3s and fuse was blown
c. it ran normal
d. none of the mentioned
Q. avoided by using
a. a turn or two of cumulative compounding
b. compensating winding
c. stablizer winding
d. all of the mentioned
Q. 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. 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