Which D.C. motor has got maximum self relieving property ?

In a D.C. generator all of the following could be the effects of iron losses except___________?

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

Which of the following loss in a D.C. generator is dissipated in the form of heat?

A. Mechanical loss
B. Core loss
C. Copper loss
D. All of the above

In variable speed motor___________?

A. a stronger commutating field is needed at low speed than at high speed
B. a weaker commutating field is needed at low speed than at high speed
C. same commutating field is needed at low speed than at high speed
D. none of the above is correct

Ward-Leonard control is basically a____________?

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

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

In case of conductively compensated D.C. series motors, the compensating winding is provided______________?

A. as separately wound unit
B. in parallel with armature winding
C. in series with armature winding
D. in parallel with field winding