Wear of carbon ceramic composite brushes under high loads and densities

This thesis examines sliding wear behavior of a new carbon ceramic composite material under high current densities and high loads. Wear of conventional carbon-graphite and copper-graphite carbon brushes usually increase with current density. Higher wear rates were explained partially by high temperatures in the brush --copper interface. Electric machines running at higher speeds and loads require higher performance brush materials. In particular, pantographs in electric vehicles must perform over a wide range of speeds and contact forces. Increased speeds require materials that can withstand higher current densities and pressures, without disintegrating. The materials tested were developed and manufactured by Carbon Ceramics Company, LLC. Test conditions (Speed, load and current density) approximate operating conditions in pantographs collector stripes. Measured wear rates were compared to mechanical and electrical parameters such as load, speed, friction coefficient and current density.