Top 150+ Solved DC Motor MCQ Questions Answer
Q. The purpose of retardation test on D.C. shunt machines is to find out
a. stray losses
b. eddy current losses
c. field copper losses
d. windage losses
Q. Which of the following tests will be suitable for testing two similar D.C. series motorsof large capacity ?
a. Swinburne's test
b. Hopkinson's test
c. Field test
d. Brake test
Q. Hopkinson's test on D.C. machines is conducted at
a. no-load
b. part load
c. full-load
d. overload
Q. During rheostat braking of D.C. series motors
a. motor is run as a generator
b. motor is reversed in direction
c. motor is run at reduced speed
d. none
Q. For which types of D.C. motor, dynamic braking is generally used ?
a. Shunt motors
b. Series motors
c. Compound motors
d. All of the above
Q. Which method of braking is generally used in elevators ?
a. Plugging
b. Regenerative braking
c. Rheostatic braking
d. None of the above
Q. In variable speed motor
a. a stronger commutating field is needed at low speed than at high speed
b. a weaker commutating field is needed at low speed than at high speed
c. same commutating field is needed at low speed than at high speed
d. none of the above is correct
Q. When the armature of a D.C. motor rotates, e.m.f. induced is
a. self-induced e.m.f.
b. mutually induced e.m.f.
c. back e.m.f.
d. none of the above
Q. Where D.C. motor of H.P. 12 or more requires frequent starting, stopping, reversing and speed control
a. drum type controller is used
b. three point starter is used
c. four point starter is used
d. all above can be used
Q. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens
a. this will make armature to take heavy current, possibly burning it
b. this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
c. nothing will happen to motor
d. motor will come to stop
Q. D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the
a. series motor
b. shunt motor
c. compound motor
d. any of the above
Q. D.C. motor is to a drive a load which is almost nil for certain part of the load cycleand peak value for short duration. We will select this
a. series motor
b. shunt motor
c. compound motor
d. any of the above
Q. Which D.C. motor has got maximum self relieving property ?
a. Series motor
b. Shunt motor
c. Cumulatively compounded motor
d. Differentially compounded motor
Q. In the D.C. motor the iron losses occur in
a. the field
b. the armature
c. the brushes
d. the commutator
Q. The speed of a D.C. shunt motor is required to be more than full load speed. This ispossible by
a. reducing the field current
b. decreasing the armature current
c. increasing the armature current
d. increasing the excitation current