Electrical and tribological behaviour of gold/gold sliding contacts of the wire/ring type for slip ring applications

Many industrial systems require the transmission of electrical current from a static part to a rotating one. This is achieved by a sliding contact within a slip ring device. These devices usually have to be fully operative for many years. Understanding the wear mechanism and the electrical behaviour are of major interest. In order to study the triboelectrical behaviour of sliding contacts of the wire/ring type, a rotating ball-on-disc tribometer (Anton Paar TRB³) has been used. The friction of a wire on a ring is reproduced by the friction of a wire on a disc thanks to a special wire holder. The gold alloy wire is the same as in the real slip ring device and the brass disc has the same gold alloy plating as in real slip rings. Voltage drop through the interface is measured with the 4-probes method. This set-up allows to study the influence of various parameters such as rotating speed, current value, normal force, lubrication conditions, and more. In this paper, the new experimental setup, and the first results obtained during its implementation are presented.