Difference Between Brushed & Brushless Motors

Brushed or brushless? Which one is better? You've probably noticed that tools with brushless DC motors are higher in price than brushed. Does that mean their performance is higher? Whether it's brushed or brushless, these motors are both rotating because of the same thing: magnets. Just like putting two same sides of a magnet together (N & N or S & S), they push away. This is the same force that keeps the motor shaft continuously rotating.

Brushed Motors

In a brushed motor, electricity (whether it's corded or cordless) comes through two spring-loaded carbon brushes located on each side of the motor's shaft (the spring keeps the physical contact between the brushes and the commutator). The brushes come into contact with the commutator, a part of the motors that is fixed to the motor shaft. The commutator then transfers that electric current to the armature which is also attached to the motor shaft. The armature is made up of tightly wrapped bundles of copper wiring which the electricity travels through, creating an electromagnetic field. Fixed magnets are located outside of the motor that spin the motor when the armature becomes electromagnetically charged. It will continue spinning until the charge from the battery stops.

Pros of the brushed motor are that it's a simple structure and it's lower in price.

A con of the brushed motor is that the brushes are in physical contact with the commutator. This results in friction (causing a loss of energy) and wear and tear. Brushes require replacing after a period of time.

Brushless Motors

Brushless motors are not a marketing scheme, there is a legitimate physical difference in structure and operation of the tool. In a brushless motor, the positions of the armature and the magnets are switched. The armature is fixed outside the motor and the magnets are on the rotor part of the of the motor. There is no commutator and NO carbon brushes (brushless). You might now be wondering, how does the electric current travel without the brushes? WELL...

The brushless motor features a very small circuit board that regulates the power traveling to the armature (this is why brushless is a little pricier than brushed). There is a sensor that detects the motion of the rotor and when the circuit board distributes electric current to the armature, the same electromagnetic field is born and voila, the motor shafts starts spinning!

The sensor in a brushless motor also benefits the user by maintaining a power supply adapted to the application at hand (often brushless tools are called "smarter" tools). The more resistance the object that is being worked on has, the more electric current will be released because of the sensor. Brushed consistently only run on its maximum speed when in use.

Pros & Cons

Pros of brushless motors are that it has little-to-no friction, making it more efficient, therefore a battery and run time will last longer. Brushless motors are also lower maintenance because they don't have carbon brushes.

The con of the brushless motor is the increase in cost compared to brushed motor tools.

Fun factoid: the brushless electric motor was first introduced by Makita!