Graphite Brushes

Electrographite, the most important raw material, and the binder pitch or resin are heat-treated similarly to hard carbon. The principle field or application for carbon graphite brushes is, therefore, intermediate between those of electrographitic and hard carbon brushes. Their polishing properties are better: their elctrical carrying is lower thatn in the case of electrographitc brushe. Carbon graphite brushes are also characterized by putstanding commutating abilities as a result of their high contact drop. They are used on machines where electrographics brushes cannot be used due to their low polishing ability, and where hard cabon are unsuitable because opf their lower commutationg prosperies. Carbon graphite brushes are mainly used on F.H.P. motors with mica undercut and on small thyristo fed DC machines.