A slip ring (in electricalengineering terms) is a method of making an electricalconnection through a rotating assembly. Slip rings, also calledrotary electrical interfaces, rotatingelectrical connectors, collectors,swivels, or electrical rotaryjoints, are commonly found in electricmotors, electricalgenerators for AC systemsand alternators and inpackaging machinery, cable reels, and wind turbines.

A slip ring is a rotary coupling used to transfer electriccurrent from a stationary unit to a rotating unit. Either thebrushes or the rings are stationary and the other componentrotates. ^[1][2]

This system is similar to the brushes andcommutator,found in many types of DC motors. Whilecommutators are segmented, slip rings are continuous, and the termsare not interchangeable. Slip rings can also be used whereelectrical power or signals need to be transferred to a rotatingdevice, such as an aerodromebeacon, rotating tank,power shovel,radio telescopeor heliostat. Rotarytransformers are often used instead of slip rings in high speedor low friction environments.