A slip ring (in electrical engineering terms) is a method of making an electrical connection through a rotating assembly. Slip rings, also called rotary electrical interfaces, rotating electrical connectors, collectors, swivels, or electrical rotary joints, are commonly found in electric motors, electrical generators for AC systems and alternators and in packaging machinery, cable reels, and wind turbines.A slip ring is a rotary coupling used to transfer electric current from a stationary unit to a rotating unit. Either the brushes or the rings are stationary and the other component rotates. [1] [2]This system is similar to the brushes and commutator, found in many types of DC motors. While commutators are segmented, slip rings are continuous, and the terms are not interchangeable. Slip rings can also be used where electrical power or signals need to be transferred to a rotating device, such as an aerodrome beacon, rotating tank, power shovel, radio telescope or heliostat. Rotary transformers are often used instead of slip rings in high speed or low friction environments.
