Slipkontakt

Slipkontakt, or sliding electrical contact, is a means of transferring electrical power or signals between a stationary part and a rotating part via a sliding interface. The most common realization is a slip ring with conductive rings mounted on the rotating assembly and carbon or metal brushes pressed against the rings by springs. As the rotor turns, the brushes slide over the rings, maintaining electrical contact and allowing a load to receive power or data without a cord twisting around the shaft. Multiple rings permit several independent circuits, enabling both power supply and sensor lines to pass through the same mechanical joint.

Materials and operation: The sliding interface relies on materials such as carbon (graphite), carbon–graphite composites, or copper alloys that provide conductivity and some self-lubrication. The contact resistance generates heat, so designs specify current and voltage ratings, speed, and cooling. Wear is inevitable, so preload, brush shape, ring surface finish, and lubrication are important to reduce wear, arcing, and electrical noise. Regular inspection of brushes, rings, and seals is part of maintenance.

Applications: Slipcontacts are widely used in rotating electrical equipment where a continuous electrical connection is needed, including DC motors and generators, wind turbine nacelles, cranes and hoisting gear, rotary antennas, medical imaging gantries, test rigs, and laboratory equipment. They also enable data transmission through multiple channels.

Design considerations: Engineers balance electrical requirements (current, voltage, impedance), mechanical constraints (speed, vibration, alignment), and environmental factors (dust, moisture, temperature). Reliability is affected by wear, corrosion, and spark generation; protective housings, proper lubrication, and, in some cases, non-contact alternatives such as wireless power transfer or rotary transformers are considered for long life or high-speed applications.