Top 150+ Solved Electrical Drives and Controls (EDC) MCQ Questions Answer
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
Q. With a P-pole DC machine with armature current Ia, the current per brush arm for a lap connected windings is?
a. ia/p
b. ia/2p
c. 2ia/p
d. ia/4p
Q. unused component in the machine, then we must
a. s/p/2 should not be an integer
b. s/p/2 should be integer
c. s/p should be integer
d. s/p should not be an integer
Q. While doing regular checks on the dc machine with the lap connected winding, it is reported to have ammeter fluctuations, this can be due to
a. different air gaps under poles
b. variable reluctances in the core
c. irregular design deformations
d. all of the mentioned
Q. with the remaining brushes, voltage and power that could be obtained from the machine are
a. e, p
b. e, 2p/3
c. e/p, 2p/3
d. e, p/3
Q. Ward Leonard method is
a. armature control method
b. field control method
c. combination of armature control method and field control method
d. totally different from armature and field control method
Q. Reducing the armature voltage will give us
a. variable torque speed control
b. constant torque speed control
c. variable and constant both can be achieved
d. cannot comment on torque
Q. b) DC generator
a. reduce armature voltage
b. increase armature voltage
c. increase field current
d. decrease field current
Q. Reducing the field current will give us
a. constant torque and variable power speed control
b. constant torque speed control
c. variable power speed control
d. constant power speed control
Q. Speed-power characteristic for Ward Leonard speed control method
a. will start from origin
b. will start from some positive value on power axis
c. will start from some positive value on speed axis
d. depends on other parameters
Q. Efficiency of Ward Leonard method is
a. higher than rheostatic control method but lower than shunted field control method
b. lower than rheostatic control method
c. higher than rheostatic control method and shunted field control method
d. depends on load