Patent ID: 8395297

Claim:
An electric machine, comprising: a rotor; a commutator; and at least two pairs of carbon brushes, each pair including one plus carbon brush and one minus carbon brush; and at least two pairs of brush holders for holding the at least two pairs of carbon brushes, wherein for each carbon brush and a corresponding brush holder holding the carbon brush, an axis of symmetry of the carbon brush extending through the carbon brush is substantially parallel to an axis of symmetry of the corresponding brush holder extending through the brush holder; wherein the carbon brushes interact with the commutator to supply current to the rotor; wherein the plus and minus carbon brushes of each pair lie opposite one another at the commutator; wherein the plus and minus carbon brushes of each pair are coupled to corresponding brush holders and mounted on a brush plate using respective mounts, wherein each mount includes a holding part on the brush plate and a holding part on the brush holder, the mounts for the plus and minus carbon brushes of each pair lying across from each other at 180 degrees; wherein, in order to achieve an asymmetrical placement of the carbon brush, the holding part on at least one brush holder is offset from the axis of symmetry of the at least one brush holder by an angle relative to a rotational axis of the rotor, and wherein the holding part on other brush holders is disposed on the axis of symmetry of the respective brush holder.