ABSTRACT
A brush is an electrical conductor that acts as a sliding contact to carry current to and from a rotating surface, the most common forms of which are known as a commutator or slip ring. The brush may be anodic or positive, where the current flow is from the brush to the collector, and cathodic or negative, where the current flow is from the collector to the brush. Ideal commutation occurs when the current reversal takes place at a constant rate from full current at the instant the brush contacts the commutator bar to full current in the reversed direction at the instant the brush leaves the commutator bar. The manufacture of electrographitic brush materials is an engineered process which is carried out with the technique, pride, and skill of expert craftsmen. As a brush material, the electrographitic grades of material generally have the best commutating characteristics and the lowest friction coefficients.
