In addition to the required service life (e.g. 2500 washing cycles in the case of washing machines), noise behaviour and, in particular, radio interference suppression are major subjects of consideration in relation to carbon brushes. Only specially adapted materials (manufactured in part through complex finishing treatment) meet these requirements. Composite graphite and electrographite form the basic structure of these materials. Depending on the requirement profile, these are impregnated. In addition to mechanical and electrical characteristics, undesired radio interference or noise development, for example, can be reduced. Motor manufacturers can reduce the integration of suppression agents and save production costs. Carbon brush design also has a decisive influence on the behaviour of frictional contact.
Pre-finished systems in particular consisting of a carbon brush, holder system and collector are in demand today, due to efficiency reasons. These also include rotating brush rockers in which suppression components, heat monitors and switches are integrated.