Category: D.C. Motors

A. independent of armature current
B. directly proportional to the armature current
C. proportional to the square of the current
D. inversely proportional to the armature current

A. Field copper loss
B. Windage loss
C. Armature copper loss
D. None of the above

A. low
B. around 500 Q
C. 1000 Q
D. infinitely large

A. torque will remain constant
B. torque will change but power will remain constant
C. torque and power both will change
D. torque, power and speed, all will change

A. to improve cooling
B. to reduce copper losses
C. to increase the generated e.m.f.
D. to reduce the sparking

A. voltage control method
B. field divertor method
C. field control method
D. armature resistance control method

A. decreasing the field current
B. increasing the field current
C. decreasing the armature current
D. increasing the armature current

A. shunt motors
B. shunt as well as compound motors
C. shunt, compound and series motors
D. all D.C. motors

A. Series motor
B. Shunt motor
C. Cumulatively compounded motor
D. Differentially compounded motor

A. where load is constant
B. where load changes frequently
C. where constant operating speed is needed
D. in none of the above situations