Slip rings are made of steel, copper or phosphor bronze. The material of the slip ring must be harder than the material of the carbon brush. To ensure that the slip ring is not worn.

Generally, slip rings consist of fixed graphite or metal contacts (brushes). They rub against the outer diameter of the rotating metal ring. When the metal ring rotates, a current or signal is conducted to the connected metal ring through a fixed brush. If many circuits are required, other ring / brush assemblies are stacked along the axis of rotation. The brush or ring is either fixed or the other parts rotate.

This simple design has been used for decades. As a basic method of delivering electrical current to rotating equipment.