What is the difference of DC voltages in adjoining brushes?

Question

Question

This question was previously asked in

RRB ALP Instrument Mechanic 23 Jan 2019 Official Paper (Shift 1)

Answer 1

The difference in DC voltages between adjoining brushes in a DC machine depends on the machine's design and operating conditions.
In a DC machine, the voltage difference between adjoining brushes is influenced by factors such as the number of poles, armature speed, and the configuration of the winding.
Under normal operating conditions in a well-designed DC machine, the difference in DC voltages between adjoining brushes is typically very close to zero.
This is because the brushes are in physical contact with the commutator segments, ensuring electrical continuity and a relatively uniform voltage distribution along the commutator.
The voltage drop across each brush is negligible when compared to the overall voltage supplied to the armature.

Here, option 3 is correct.

Download Solution PDF