# Slip ring > Rotary electrical joint that passes power and signals from a fixed part of a machine to a part that turns without limit. Also known as: rotary electrical joint, rotary electrical connection, electrical rotary union. Category: Hardware. A slip ring is a rotary electrical joint that passes power or signals between the stationary and the rotating part of a machine. Conductive rings turn with the rotating part while stationary brushes stay in sliding contact with them, so the rotating part can turn continuously in one direction without any cable winding up. Each ring carries one circuit, so a slip ring for mains power has separate rings for phase, neutral and protective earth, and further rings can carry control signals. Slip rings are used wherever something has to rotate without limit and stay powered, from radar antennas and wind turbines to motorised turntables. Related designs solve the same problem differently. A mercury-wetted rotary contact replaces the sliding brushes with liquid metal sealed in a housing. A rotary transformer transfers power or signals without contact, by induction. The term rotary union strictly means a joint that passes fluids or air into a rotating part, but it is sometimes used loosely for electrical joints as well. ## How PhotoRobot uses it PhotoRobot uses a rotary electrical joint – typically slip rings, in some designs a mercury-wetted contact in a safely sealed housing – in its [RotoPower](https://www.photorobot.com/glossary/rotopower) option, which brings mains power into the rotating plate of the CUBE and the Turning Platform. On the Turning Platform the joint also passes two logic channels that control the belt speed of the Virtual Catwalk. ## See on photorobot.com - [CUBE](https://www.photorobot.com/robots/cube) - [Turning Platform](https://www.photorobot.com/robots/turning-platform) ## Related terms - [RotoPower](https://www.photorobot.com/glossary/rotopower): PhotoRobot option that brings mains power into the rotating part of a robot, so a product can stay switched on while it turns. - [Turning Platform](https://www.photorobot.com/glossary/turning-platform): PhotoRobot heavy-duty turntable for furniture and machinery, with plates up to 280 cm and a 1500 kg load capacity. - [CUBE](https://www.photorobot.com/glossary/cube): Versatile PhotoRobot robot – Cube V5, V6 and V6 RotoPower – used as a turntable, to suspend objects, or as a rotating mannequin holder. - [Photography turntable](https://www.photorobot.com/glossary/photography-turntable): A rotating platform that turns a product in front of a fixed camera so it can be photographed from every side. ## Where this term appears on photorobot.com Mentioned on 1 page. Most relevant: - [CUBE](https://www.photorobot.com/robots/cube): Power passes through a rotary electrical joint instead of a cable, so the plate can keep turning in one direction without limit.