Fans with brushless EC motors

A brushless motor is a direct current electric motor, with a rotor equipped with permanent magnets, instead of windings, and a stator with windings that generates a rotating magnetic field. Unlike a brush motor, it does not need sliding electrical contacts, or brushes, in contact with the motor shaft in order to operate.

The commutation of the current circulating in the stator windings, and therefore the variation of the orientation of the magnetic field generated by them, takes place electronically.

This results in lower mechanical resistance, eliminates the possibility of generating sparks as the rotation speed increases, and considerably reduces the need for periodic maintenance. Since the motor makes use of direct current, to generate the rotating magnetic field in the stator, an electronic circuit is needed. This is composed of a bank of power transistors controlled by a micro-controller, which commutates the current, causing a current inversion and therefore the rotation of the inverter magnetic field.