Collection device for collecting electrical currents, and machine comprising a collection device of this kind

A discharge device for discharging electric currents from a rotor part of a machine, said rotor part having a shaft, the discharge device comprising a displaceable contact element, which is at least partly accommodated in a guide, for forming an electroconductive sliding contact between a sliding contact surface of the contact element and a shaft contact surface of the shaft, the sliding contact surface being provided for forming the sliding contact, the contact element being electroconductively connected to the guide and/or a retaining element of the machine, and the contact element being prestressed towards the shaft contact surface by means of a spring element,

• wherein
• the contact element is at least partly wetted with an oily fluid, at least in the area of its sliding contact surface, and wherein the contact element is essentially made of a carbon-metal mixture, namely a mixture of graphite and metal, the total volume fraction of the metal being at least 30 percent by volume, silver being provided as the metal at least in a front area of the contact element, said front area having the sliding contact surface, and copper being provided as the metal in a rearward area of the contact element, the contact element being free from copper in the area of the sliding contact surface.