What is a brushed motor?

A brushed motor is a category of electric motor. They use carbon brushes to make electrical contact with the electromagnets that spin the motor’s shaft.

You probably know that magnets with opposite polarity attract each other. Electric motors use magnets to spin the rotating shaft around in a circle.

Brushed motors have electromagnets mounted on the spinning rotor. Permanent (non-electric) magnets surround them. Because the electromagnets are spinning, the motor needs some means of keeping them in electrical contact.

Carbon brushes press against the magnets as they spin. They’re arranged so the magnet alternates polarity to keep pulling the shaft around.

Brushed motors are simple and cheap to build. They’re found in a wide variety of power tools. But the brushes do cause friction since they’re in constant contact with the spinning rotor.

This friction wears them down over time, and you’ll need to replace them when they stop making contact. And the friction reduces the motor’s efficiency. Newer brushless motors are becoming more popular in power tools. They don’t have this problem with friction, so they tend to run cooler and last longer.