Electricians today have the option of choosing between copper or carbon electric brushes. While both are highly functional, there are benefits that correspond to each type of brush, depending on its intended function.
Motors depend on the connection between the coils of the rotor to complete a circuit. The brush facilitates this current connection. Traditionally, brushes were constructed of braided copper wire, although carbon brushes are widely used today.
Copper wire brushes are durable compared to modern carbon composite brushes, and exhibit high conductance, but provide comparatively poor commutation, as the copper wiring used is not as resistant.
Carbon brushes are softer, and thus wear more quickly than copper brushes, but offer high resistance and better commutation between commuter segments. Although carbon brushes have been used more widely than copper brushes in recent years, new copper and composite brushes that combine carbon and copper have been developed that offer higher performance.