A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. A slip ring can be used in any electromechanical system that requires rotation while transmitting power or signals. It can improve mechanical performance, simplify system operation and eliminate damage-prone wires dangling from movable joints.
Slip rings on a hydroelectric generator; A - stationary spring-loaded graphite brushes, B - rotating steel contact ring, C - insulated connections to generator field winding, D - top end of generator shaft.
The two most common types of slip ring
An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature. Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used. In principle, any AC electrical generator can be called an alternator, but usually the term refers to small rotating machines driven by automotive and other internal combustion engines.
Alternators made in 1909 by Ganz Works in the power generating hall of a Russian hydroelectric station (photograph by Prokudin-Gorsky, 1911).
Alternator mounted on an automobile engine with a serpentine belt pulley (belt not present.)
