To avoid formation of grooves in the commutator of a D.C. machine?

Related Mcqs:

The resistance of armature winding depends on

A. length of conductor B. cross-sectional area of the conductor C. number of conductors D. all of the above...

The insulating material used between the commutator segments is normally_____________?

A. graphite B. paper C. mica D. insulating varnish...

In a D.C. machine stray loss is the sum of_____________?

A. total copper loss and mechanical loss B. armature copper loss and iron loss C. shunt field copper loss and mechanical loss D. iron loss and mechanical loss...

In a D.C. generator in case the resistance of the field winding is increased, then output voltage will____________?

A. increase B. decrease C. remain unaffected D. fluctuate heavily...

Armature reaction in a generator results in_____________?

A. demagnetisation of leading pole tip and magnetisation of trailing pole tip B. demagnetisation of trailing pole tip and magnetisation of leading pole tip C. damagnetising the center of all poles D. magnetising the center of all poles...