Question

In a DC generator the ripples in the direct emf generated can be reduced by________

(a) Using conductor of annealed copper

(b) Using commutator with large number of segments

(c) Using carbon brushes of superior quality

(d) Using equalizer rings

This question was posed to me by my college director while I was bunking the class.

My question comes from Brushes and Commutator Assembly topic in section DC Machines of DC Machines

Answer 1

Right option is (c) Using carbon brushes of superior quality

For explanation I would say: Brushes carry current to/from rotating parts from/to stationary part. Ripples can be avoided if brushes are maintained. Else, brushes will have some voltage drop in it and we’ll not get simple repeating part in emf.