Question

What is the voltage drop in the carbon and graphite brushes?

(a) 1 V

(b) 0.3 V

(c) 0.6 V

(d) 0.75 V

The question was posed to me in final exam.

This key question is from Losses and Temperature Rise in portion Design of Synchronous Machines of Design of Electrical Machines

Answer 1

Right option is (a) 1 V

For explanation: The voltage drop in the carbon and graphite brushes is 1 V. The voltage drop in the brushes containing metal is 0.3 V.