DC Motors
In dc machines fractional pitch winding is used

To increase the generated emf
To improve cooling
To reduce the generated emf
To reduce the sparking

ANSWER DOWNLOAD EXAMIANS APP

DC Motors
In variable speed motor

A weaker commutating field is needed at low speed than at high speed
None of these
Same commutating field is needed at low speed than at high speed
A stronger commutating field is needed at low speed than at high speed

ANSWER DOWNLOAD EXAMIANS APP

DC Motors
If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens

This will make armature to take heavy current, possibly burning it
Motor will come to stop
Nothing will happen to motor
This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses

ANSWER DOWNLOAD EXAMIANS APP