Quick Guide: What is a Brushless Lawn Mower?

Electric motors range in size from tiny toothbrush motors to gigantic electric motors providing propulsion to ocean liners, and as such, they are often used not only in electric lawn mowers but also in electric trimmers, chainsaws, blowers, etc.

While electric motors differ in many ways, one of their construction specifics is that they can be divided into brushed and brushless electric motors, with all their pros and cons.

Published: November 3, 2022.

Brushed vs. Brushless Motor

There is a big difference in the construction of brushed (older type) and brushless (newer type) electric motors.

Brushed electric motors consist of electric windings on the rotor, while the stator consists of either permanent magnets or electric windings.

For a brushed motor to operate, electric energy is transferred to the rotor windings via spring-loaded brushes, usually made of graphite.

As the rotor spins, spring-loaded brushes generate heat due to the mechanical resistance (although very low) and electric resistance (also very low), but they wear out over time and must be replaced after a certain number of hours of operation.

But, a brushed electric motor can operate using any suitable source of DC electricity and a simple On/Off switch.

Brushless electric motors feature rotors with permanent magnets and stators made of several different windings, mostly copper windings.

In order for the rotor to spin, the brushless motor feature a sensor that tells the controller position of the rotor allowing the controller to create a magnetic field that best fits the performance requirements.

As the rotor spins, the controller changes the magnetic field to compensate for the rotor's position change, greatly improving the energy efficiency, especially when the motor must operate at different output power levels.

While the operation of brushless motors may sound complicated, modern motor controllers are miniaturized electronic devices, thanks to advanced microchips that have almost everything integrated just in a few small microchips.

Pros and Cons of Brushless Motors

As already mentioned, brushless motors have many pros over brushed motors, including:

• better energy efficiency: thanks to the motor controller, the brushless motor features better energy efficiency than the brushed motor.
• less maintenance: brushless motors don't have spring-loaded brushes that wear over time and must be replaced periodically.
• quieter operation: brushless motors have fewer parts that rotate and that are in contact with other parts that don't rotate, for example, brushes.
• less heat generated: brushless motors generate less heat due to better energy efficiency.
• operate at higher power levels: since they are not limited by the maximum current that brushes can handle, brushless motors can operate at higher power levels.
• adjustable power levels: since they are fully controlled by electric controllers, brushless motors can operate at different output power levels, different speeds, etc.

Brushless motors have other pros as well, but these are the most important ones.

On the other hand, brushless motors can't operate without their controllers.

If You are looking for a cordless lawn mower or similar cordless tool, investing a little more in the models with brushless motors is a smart move for all the above-mentioned reasons.

However, many brands still offer low-power tools and accessories equipped with brushed motors, thanks to their simplicity and overall relatively low cost.