Top 150+ Solved DC Motor MCQ Questions Answer
Q. The current drawn by the armature of D.C. motor is directly proportional to
a. the torque required
b. the speed of the motor
c. the voltage across the terminals
d. none of the above
Q. The power mentioned on the name plate of an electric motor indicates
a. the power drawn in kW
b. the power drawn in kVA
c. the gross power
d. the output power available at the shaft
Q. Which D.C. motor has got maximum self loading property?
a. Series motor
b. Shunt motor
c. Cumulatively compounded 'motor
d. Differentially compounded motor
Q. Which D.C. motor will be suitable alongwith flywheel for intermittent light and heavyloads?
a. Series motor
b. Shunt motor
c. Cumulatively compounded motor
d. Differentially compounded motor
Q. If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens
a. nothing will happen to th£ motor
b. this will make armature to take heavy current, possibly burning it
c. this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
d. motor will run at very slow speed
Q. D.C. series motors are used
a. where load is constant
b. where load changes frequently
c. where constant operating speed is needed
d. in none of the above situations.
Q. For the same H.P. rating and full load speed, following motor has poor starting torque
a. shunt
b. series
c. differentially compounded
d. cumulativelyc'ompounded
Q. In case of conductively compensated D.C. series motors, the compensating winding isprovided
a. as separately wound unit
b. in parallel with armature winding
c. in series with armature winding
d. in parallel with field winding
Q. Sparking at the commutator of a D.C. motor may result in
a. damage to commutator segments
b. damage to commutator insulation
c. increased power consumption
d. all of the above
Q. Which of the following motor is preferred for operation in highly explosiveatmosphere ?
a. Series motor
b. Shunt motor
c. Air motor
d. Battery operated motor
Q. If the supply voltage for a D.C. motor is increased, which of the following will decrease?
a. Starting torque
b. Operating speed
c. Full-load current
d. All of the above
Q. Which one of the following is not the function of pole shoes in a D.C. machine ?
a. To reduce eddy current loss
b. To support the field coils
c. To spread out flux for better unifor-mity
d. To reduce the reluctance of the mag-netic path
Q. For which of the following applications a D.C. motor is preferred over an A.C. motor ?
a. Low speed operation
b. High speed operation
c. Variable speed operation
d. Fixed speed operation
Q. In case-the conditions for maximum power for a D.C. motor are established,theefficiency of the motor will be
a. 100%
b. around 90%
c. anywhere between 75% and 90%
d. less than 50%