A brushless DC motor (BLDC) is an electric motor powered by direct current with the permanent magnets (usually four or more) mounted in a cross pattern around the perimeter of the rotor.
Because the rotor itself bears the magnets there is no need to feed it with power rendering communicators and brushes redundant.
In brushless motor detecting the rotor’s exact position is crucial. Controllers, rotary encoders or hall sensors are used in order to ensure full synchronization between rotors and stators.
Advantages of BLDC Motors
Brushless motor comes in single, dual or tri-phase configurations. They are more accurate, so far as positioning goes, than brush DC motors. Due to lack of brushes they require virtually no maintenance.
Brushless motor better maintain, and even increase, torque at varying speeds. Another big advantage is lack of power loss across brushes (loss which, in brush motors, grows with rpm along with increase of friction between brushes and communicators).
BLDC motors are smaller in size and offer more output power, their operating noise levels (both mechanical and electrical) are low and they perform better so far as heat dissipation and speed ranges are concerned.
Versatility, compact size and wide range of speed and torque makes brushless motors ideal for many uses such as in computer hard drives, media players, electrical component cooling fans, HVAC and refrigeration compressors, direct drive turntables and industrial manufacturing machinery. BRDC motors are also found in electric and hybrid vehicles, electric bicycles, assembly robots, industrial positioning and actuation devices and many other machines and appliances.