For constant torque drive which speed control method is preferred ?

In D.C. machines fractional pitch winding is used__________?

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

Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ?

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

Ward-Leonard control is basically a____________?

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

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

Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be_____________?

A. level compounded
B. under compounded
C. cumulatively compounded
D. differentially compounded

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