What are Carbon Brushes?
A carbon brush (also known as a motor brush or electric brush) is a small part inside an electric motor, that conducts electrical current between the rotating part of the motor and the stationary part.
They’re made from carbon blocks (usually a mixture of copper graphite, electro graphite, silver graphite, natural graphite, bonded carbon, and pitch bonded carbon) which are then attached to one or multiple electrical terminals.
The reason carbon is used as opposed to another material, is because it’s such a good conductor of electricity, whilst also being soft enough to give a consistent contact point over time. This does lead to wear in the brush, however, hence the need to buy a new carbon brush every now and then.
What do Carbon Brushes do?
Carbon brushes conduct electricity between the moving and stationary parts of the motor. The main benefit of using a carbon brush is that it stops you from relying on an integral part of the motor for the connection, which would lead to eventual wear and then the failure of the motor. With a carbon brush, you have a part that’s deliberately designed to wear over time and can be easily (and cheaply) replaced.
How Expensive are Carbon Brushes?
You can usually pick up a new carbon brush set for between £3 and £7, which is significantly cheaper than replacing the whole tool. Your tool may need several brushes though, so check before ordering.