Brush (electric)

In order to maximize electrical conductivity and green strength, highly dendritic (electrolytic) copper powder is used.

[5] Binders, mostly phenol or other resins or pitch, are mixed in so the powder holds its shape when compacted.

Much know-how and research is needed in order to define a brush grade mixture for each application or motor.

The brush compound is compacted in a tool consisting of upper and lower punch and die, on mechanical or hydraulic presses.

The heat treatment is transformed by a temperature curve exactly defined for each material mixture.

Some companies use additional treatments in order to make the brush more durable by methods such as impregnation of the running surface by special oils, resins and grease.

[7] Manufacturing of carbon brushes requires an in-depth knowledge of materials and experience in mixture compositions.

Drawbacks to this approach include the need to contain the liquid metal (as it is usually toxic or corrosive) and power losses from induction and turbulence.