Brushless and brushed drills, impact drivers, circular saws, and more exist as options. It isn’t just the carbon brush that differentiates brushless and brushed motors. Both harness the power of an electromagnetic field to turn the shaft. But they go about generating that field using different methods. Brushed motors do it mechanically, while brushless motors do it electronically.
It’s essential to understand what a brush is in the context of power tool motors. Brushes are simply small blocks of metal, usually carbon, mounted against a motor’s commutator. They don’t have bristles, they’re fixed in place, and they don’t clean anything. The brush’s only job in the motor is to deliver electric current to the commutator. The commutator then energizes the motor’s coils in an alternating pattern to generate an electromagnetic field that turns the motor shaft. The commutator and brushes setup has been around for decades, and you’ll still find them in powerful drills, rotary tools, and more.
Brushless technology does away with both brushes and commutators. Instead, they employ a ring of permanent magnets around the motor coils. The electromagnetic field spins the permanent magnets when the coils are energized, turning the shaft. These types of motors use a Hall effectt sensor to constantly monitor the position of the rotor and energize each motor coil exactly when needed to sustain the stability and speed of the spin.
Doing away with components that require physical contact to deliver electricity makes brushless motors superior to their brushed counterparts in many ways. Including increased energy efficiency, improved responsiveness, greater power, torque, and speed, less maintenance, and a longer overall lifespan for the tool.