Top 250+ Solved Electrical and Electronics Engineering MCQ Questions Answer
Q. A 20HP DC motor has 89.3% efficiency at rated power. What are its total losses?
a. 1787w
b. 1232w
c. 2184w
d. 1572w
Q. By flux control method of speed control of a dc shunt motor, we can obtain speeds.
a. above the normal speed only
b. below the normal speed only
c. above as well as below the normal speed
d. none of the above
Q. By putting controller resistance in series with the armature of a DC motor, we can obtain speeds
a. above the normal speed only
b. below the normal speed only
c. above as well as below the normal speed
d. none of the above
Q. Motor starters are essential for
a. accelerating the motor
b. starting the motor
c. avoiding excessive starting current
d. preventing fuse blowing
Q. The only disadvantage of field control method for controlling the speed of a dc shunt motor is that it
a. gives speeds lower than the normal speed
b. is wasteful
c. needs a large rheostat
d. adversely affects commutation
Q. When quick speed reversal is a consideration, the motor preffered is
a. synchronous motor
b. squirrel cage induction motor
c. wound rotor induction motor
d. dc motor
Q. The range of horse power of electric motor drives for rolling mills is of the order of
a. 1 to 10 hp
b. 15 to 25 hp
c. 50 to 100 hp
d. 100 to 500 hp
Q. Motors preferred for rolling mill drive is
a. dc motors
b. ac slip ring motors with speed control
c. any of the above
d. none of the above.
Q. Cumulatively compounded motors are used where we require _____.
a. light duty excavators
b. medium duty excavators
c. heavy duty excavators
d. all of the above
Q. Which type of motors are preferred in lifts?
a. dc compound motors.
b. b. dc series motors.
c. dc shunt motors.
d. none of the above.
Q. In cloth washing machines and refrigerators which motors are preferred?
a. dc cumulative compound motors
b. b. slip ring im
c. stepper motor
d. universal motors
Q. In lathes, milling and grinding machines which motor will preferred?
a. dc shunt motors
b. b. cage induction motor
c. synchronous motor
d. either a or b
Q. In planners which of following motors are preferred?
a. dc shunt motor
b. b. dc compound motor
c. any of above
d. none
Q. In iron and steel industry which motors are preferred?
a. induction motors
b. b. synchronous motors
c. dc shunt wound motors
d. pipe motors
Q. A sinusoidal voltage of frequency 1 Hz is applied to the field of a d.c generator. The armature voltage will be
a. 1 hz square wave
b. 1 hz sine wave
c. d. c voltage
d. zero