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Gibbons jargon buster #10: What are electric motor brushes?

Here’s the latest in our series of occasional blogs clearing up some of the terminology used in our industry. Today we’re asking: what are electric motor brushes? Read on as we reveal all…

In electric motors, power must be transferred from the stator (stationary part) to the rotor (rotating part, or shaft) in order to complete an electrical circuit. However, if wires were attached to a spinning rotor, then they would quickly get knotted up! Therefore, in order for the shaft in an electric motor to turn, devices called brushes are used.

Brushes are connected to the stator and consist of a spring attached to a piece of conducting material. A commutator (switch) is affixed to the shaft, with the springs pushing the brushes onto it. As the rotor turns, it is in constant contact with the brushes, which completes the circuit. Brushes are so called because they brush against the commutator while the rotor turns.

Originally, strands of copper wire were used for brushes due to the metal’s high conductivity. However, brushes are now often made out of carbon as it’s known to be a good conductor and wears more evenly than copper. Carbon is also softer than copper, which has a tendency to scratch the commutator and damage it.

As brushes are subjected to a great deal of abrasion, they eventually wear out and must be replaced, preferably by a competent engineer. Gibbons have offered an electric motor rewinds and repair service for 45 years and provide free collection and delivery within a 50-mile radius of our workshop in Tollesbury, Essex. Our rates are competitive and we offer an emergency same-day or next-day service wherever possible.

So if you have an electric motor repair or rewind enquiry, give us a call on 01621 868138 or email and we’ll be happy to help.

Electric Motors

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