The invention relates to an electric machine, in particular a commutator machine (10), the carbon brushes (14) of which cooperate with a commutator (13) to supply the rotor with current, the carbon brushes (14) being continuously provided or provided in layer sections with different additives such as scouring material, lubricants or similar. To achieve a longer service life for the carbon brushes (14), a maximum of half, preferably less than half of all the carbon brushes (14) of the machine have a significant fraction of an additive, said fraction differing from that of the other carbon brushes (14).