Electric Motor Brushes

Metal fiber brushes are currently being developed again. These brushes may have advantages over current carbon brushes, but have not yet seen wide implementation.

In electrical engineering, brushes conduct current between stationary wires and moving parts, most commonly in a rotating shaft. Most importantly, in an electric motor, an alternator or electric generator, the coils of the rotor have to be connected.

To accomplish this, two metal (copper or brass) 'slip rings' are affixed on the shaft and springs press braided copper wire 'brushes' onto the rings which conduct the current. Later, these copper wire brushes were replaced with carbon blocks — but these blocks are still called brushes. As the brushes are slowly abraded, they may have to be replaced, if this is possible.

If the copper rings are split into parts with "interlaced" connections, the arrangement is called a commutator.