Electrical machine having a stator and a rotor, wherein a winding for the generation of an electromagnetic field is fitted to the rotor, and having an apparatus for the supply of electrical energy to the winding, - wherein the apparatus comprises a slip ring, which is non-rotationally mounted on the rotor, and a brush assembly, comprising a brush holder and a brush which is fitted to the brush holder, - wherein, in service, the brush slides against the slip ring, - having a housing, in which the slip ring and the brush assembly are arranged, - wherein the housing, in the region of the slip ring, is radially spaced from the slip ring, and extends in a circumferential direction around the slip ring, such that an annular gap extending in the circumferential direction is constituted between the slip ring and the housing, - wherein the housing comprises a housing part, which projects radially away from the housing in radial proximity of the annular gap, - wherein a first flow opening and a second flow opening respectively terminate in the annular gap, and are mutually spaced from one another in the circumferential direction, - in that the housing part is fluidically connected to the annular gap via the flow openings (20, 21), characterized - in that the housing is fluidically substantially sealed vis-à-vis the exterior, and a flow path of air is routed through the housing in a closed arrangement, - in that a flow section of the flow path is routed through the housing part, and leads from the first flow opening via an impact wall with which the air collides and/or a chamber wherein dust is captured and stored to the second flow opening, - in that the housing part delimits the flow section. - wherein the apparatus comprises a slip ring, which is non-rotationally mounted on the rotor, and a brush assembly, comprising a brush holder and a brush which is fitted to the brush holder, - wherein, in service, the brush slides against the slip ring, - having a housing, in which the slip ring and the brush assembly are arranged, - wherein the housing, in the region of the slip ring, is radially spaced from the slip ring, and extends in a circumferential direction around the slip ring, such that an annular gap extending in the circumferential direction is constituted between the slip ring and the housing, - wherein the housing comprises a housing part, which projects radially away from the housing in radial proximity of the annular gap, - wherein a first flow opening and a second flow opening respectively terminate in the annular gap, and are mutually spaced from one another in the circumferential direction, - in that the housing part is fluidically connected to the annular gap via the flow openings (20, 21), characterized - in that the housing is fluidically substantially sealed vis-à-vis the exterior, and a flow path of air is routed through the housing in a closed arrangement, - in that a flow section of the flow path is routed through the housing part, and leads from the first flow opening via an impact wall with which the air collides and/or a chamber wherein dust is captured and stored to the second flow opening, - in that the housing part delimits the flow section.