Category: D.C. Motors

A. back e.m.f. is less than the applied voltage
B. back e.m.f. is equal to the applied voltage
C. back e.m.f. of rotor is more than the applied voltage
D. none of the above

A. drum type controller is used
B. three point starter is used
C. four point starter is used
D. all above can be used

A. shunt
B. series
C. differentially compounded
D. cumulativelyc’ompounded

A. magnetic field
B. active length of the conductor
C. current flow through the conductors
D. number of conductors
E. radius of armature
F. all above factors

A. The motor will stop
B. The motor will continue to run
C. The armature may burn
D. The motor will run noisy

A. Series motor
B. Shunt motor
C. Cumulative compound motor
D. Differential compound motor

A. Providing laminations in armature core
B. Providing laminations in stator
C. Using non-magnetic material for frame
D. Using material of low hysteresis co-efficient for armature core material

A. Loss of efficiency
B. Excessive heating of core
C. Increase in terminal voltage
D. Rise in temperature of ventilating air

A. self-induced e.m.f.
B. mutually induced e.m.f.
C. back e.m.f
D. none of the above

A. has its field winding consisting of thick wire and less turns
B. has a poor torque
C. can be started easily without load
D. has almost constant speed