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 , 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 , 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 . <EOS>