Category: D.C. Motors

A. high initial cost
B. high maintenance cost
C. low efficiency at Hght loads
D. all of the above

A. back e.m.f. = 2 x supply voltage
B. back e.m.f. = | x supply voltage
C. supply voltage = | x back e.m.f
D. supply voltage = back e.m.f

A. the motor will first stop and then run in opposite direction as series motor
B. the motor will work as series motor and run at slow speed in the same direction
C. the motor will work as series motor and run at high speed in the same direction
D. the motor will not work and come to stop

A. Frame
B. Shaft
C. Commutator
D. Stator

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

A. almost negligible
B. rated full-load current
C. less than full-load current
D. more than full-load current

A. Shunt motors
B. Series motors
C. Compound motors
D. All of the above

A. over load relay is connected in series and no volt relay in parallel with the load
B. over load relay is connected in parallel and no volt relay in series with the load
C. over load relay and no volt relay are both connected in series with the load
D. over load relay and no volt relay are both connected in parallel with the load

A. Hysteresis losses
B. Eddy current losses
C. Copper losses
D. Windage losses

A. centrifugal pumps
B. elevators
C. steel rolling mills
D. colliery winders