The Function of Carbon Brushes in Electric Motors

The carbon brushes (or brushes) in an electric motor serve one core purpose: to supply power to the rotating rotor and conduct electrical commutation.

I. What It Does, Simply Put

Conducting Electricity

It transfers current from the external power source, from the stationary stator to the high-speed rotating rotor.

Commutation (Key Function)

In brushed DC motors, they work with the commutator to continuously reverse the current direction in the rotor windings, enabling the rotor to spin continuously in one direction instead of stopping halfway.

Current Extraction

In generators, the process is reversed: they extract electricity generated by the rotor from the rotating assembly and deliver it to the external circuit.

II. Why Carbon?

Excellent conductivity and wear resistance

High-temperature tolerance, preventing sticking to the commutator

Self-lubricating properties reduce friction and noise

III. In a Nutshell

Carbon brushes serve as the motor's “rotating electrical connectors,” ensuring smooth current flow in and out to keep the motor spinning continuously.