What Is a Brushless Motor?

The article How Electric Motors Work explains how brushed motors work in great detail. In a typical DC motor, there are permanent magnets on the outside and a spinning armature on the inside. The permanent magnets are stationary, so they are called the stator. The armature rotates, so it is called the rotor.

The armature contains an electromagnet. When you run electricity into this electromagnet, it creates a magnetic field in the armature that attracts and repels the magnets in the stator. So the armature spins through 180 degrees.

To keep it spinning, you have to change the poles of the electromagnet. The brushes handle this change in polarity. They make contact with two spinning electrodes attached to the armature and flip the magnetic polarity of the electromagnet as it spins.

This setup works and is simple and cheap to manufacture, but it has a lot of problems:

With the advent of cheap computers and power transistors, it became possible to "turn the motor inside out" and eliminate the brushes. In a brushless DC motor (BLDC), you put the permanent magnets on the rotor and you move the electromagnets to the stator. Then you use an electronic speed controller (ESC) to deliver electric signals that determine rotation speed and direction [source: Joner]. This system has all sorts of advantages:

The only disadvantage of a brushless motor is its higher initial cost, but you can often recover that cost through the greater efficiency over the life of the motor.

Brushless motors represent a leap forward in electric motor technology, offering advantages that include efficiency, durability, and low maintenance. Their versatility and performance make low power brushless motors suitable for a wide range of applications, from consumer electronics to industrial machinery.

As technology continues to evolve and advance, the use of BLDC motors is only expected to grow, further solidifying their position as a critical component in modern electrical and industrial engineering and design.