Mercotac Electric Slip ring
A slip ring is an electrical connector designed to carry current or signals between a stationary wire and a rotating device.
Typically, it is comprised of a stationary graphite or metal contact (brush) which rubs on the outside diameter of a rotating metal ring. As the metal ring turns, the electrical current or signal is conducted through the stationary brush to the metal ring making the connection. Additional ring/brush assemblies are stacked along the rotating axis if more than one electrical circuit is needed.
This simple design has been used for decades as a rudimentary method of passing current into a rotating device. Some other names used for slipring are collector ring, rotary electrical contact and "electrical slip ring". Some people also use the term commutator, however commutators are somewhat different and are specialized for use on DC motors and generators.