A discharge device for discharging electric currents in a machine from a rotor part to a stator part, the rotor part in particular having a shaft, the discharge device comprising a contact element and a spring being connectable to the stator part in an electrically conductive manner, the contact element made predominantly of carbon, the contact element pressurized with a contact force by the spring for realizing an electrically conductive sliding contact between a sliding contact surface of the contact element and an axial shaft contact surface of the shaft. The contact element is circular, the sliding contact surface being at least annular in shape and disposed coaxially in relation to the shaft contact surface, the spring includes a circular support section which at least in part coaxially envelops the shaft of the machine, the support section being configured for radially abutting against an abutment surface of the stator part.

The lifetime of sliding contact surface(s) of a precious metal or a precious metal alloy can be enhanced by embedding at least one nano-particle in the layer forming the sliding contact surface(s).

A combined cooling and abrasion particles removal system and method for providing cooling and removing abrasion particles in a contact region between a brush and a slip ring of an electromechanical machine, the system comprising a passage for accommodating the brush and having a front opening adapted to face the slip ring, at least one supply tube with an outlet for blowing a gaseous medium at least partially into a direction towards a free space adjacent to the front opening, and at least one suction tube with an inlet opening for sucking off the gaseous medium and the abrasion particles from the free space. In order to pick up abrasion particles and provide sufficient cooling, the free space merges with a vortex chamber for generating a vortex of the gaseous medium carrying the abrasion particles in operation of the system.

The invention relates to a discharge device (10) for discharging electric currents from a rotor part of a machine to a stator part of the machine, the rotor part in particular having a shaft, the discharge device comprising a contact element (11) and a spring means (12), the spring means being connectable to the stator part in an electrically conductive manner, the contact element being made predominantly of carbon, the contact element being pressurized with a contact force by means of the spring means for realizing an electrically conductive sliding contact between a sliding contact surface (13) of the contact element provided for realizing the sliding contact and an axial shaft contact surface of the shaft. The contact element is circular, the sliding contact surface being at least annular in shape and being disposed coaxially in relation to the shaft contact surface, the spring means comprising a circular support section (15) which at least in part coaxially envelops the shaft of the machine, the support section being configured for radially abutting against an abutment surface of the stator part.

A combined cooling and abrasion particles removal system and method for providing cooling and removing abrasion particles in a contact region between a brush and a slip ring of an electromechanical machine, the system comprising a passage for accommodating the brush and having a front opening adapted to face the slip ring, at least one supply tube with an outlet for blowing a gaseous medium at least partially into a direction towards a free space adjacent to the front opening, and at least one suction tube with an inlet opening for sucking off the gaseous medium and the abrasion particles from the free space. In order to pick up abrasion particles and provide sufficient cooling, the free space merges with a vortex chamber for generating a vortex of the gaseous medium carrying the abrasion particles in operation of the system.