Top 250+ Solved Electrical and Electronics Engineering MCQ Questions Answer
Q. Which of the following parameters of induction motor varies inversely as the supply freq
a. full load speed
b. starting current
c. slip
d. maximum running torque
Q. When the supply voltage for an induction motor is reduced by 10%, the maximum running torque will be
a. decrease by 10%
b. decrease by 20%
c. increase by 10%
d. increase by 20%
Q. If the supply freq of an induction motor is increased by 5%, the synchronous speed will
a. decrease by 10%
b. decrease by 5%
c. increase by 5%
d. increase by 10%
Q. The direction of rotation of field in a 3-ph induction motor depends upon
a. number of poles
b. magnitude of supply voltage
c. supply freq
d. phase sequence of supply voltage
Q. The maximum voltage is induced in the rotor of 3-ph induction motor when it----
a. runs at no load
b. runs at full load
c. is blocked
d. none of the above
Q. When an induction motor is running at full load, rotor reactance is ------rotor resistance
a. low comparable to
b. very large compared to
c. large compared to
d. none of the above
Q. If an induction motor is running at slip s ( in decimal) the rotor output is
a. (1+s) x rotor input
b. (s-1) x rotor input
c. s x rotor input
d. (1-s) x rotor input
Q. The conditions of induction motor at no load resembles those of transformer whose secondary is……
a. short circuited
b. open circuited
c. supplying a variable resistive load
d. none of the above
Q. The input to a 3-ph induction motor is 50KW. The stator losses amount to 800W. The rotor cu loss per phase is (slip = 3%)
a. 576w
b. 492w
c. 1050w
d. 728w
Q. The input to a 3-ph induction motor is 50KW. The stator losses amount to 800W. The mechanical power developed (slip = 3%)
a. 59hp
b. 69hp
c. 47hp
d. 64hp
Q. An 8-pole , 50Hz,3-ph indduction motor running with a slip of 4% is taking 20KW. Stator losses amount 0.5KW. The total torque develped is
a. 248nm
b. 312nm
c. 195nm
d. 214nm
Q. The basic requirement of a dc armature winding is that it must be
a. a closed one
b. a lap winding
c. a wave winding
d. either b or c
Q. The sole purpose of a commutator in a dc generator is to
a. increase output voltage
b. reduce sparking at brushes
c. provide smoother output
d. convert the induced ac into dc
Q. In a dc generator, the generator, the generated emf is directly proportional to the
a. field current
b. pole flux
c. number of armature parallel paths
d. number of dummy coils