Brushless DC electric motors (BLDC), also known as electronically commutated motors (ECMs, EC motors) or synchronous DC motors, are synchronous motors powered by DC electricity via an inverter or switching power supply, which produces an AC electric current to drive each phase of the motor via a closed loop controller. The controller provides pulses of current to the motor windings that control the speed and torque of the motor.
The advantages of a brushless motor over a brushed motor are the high power to weight ratio, high speed, and electronic control. Brushless motors find applications in such places as computer peripherals (disk drives, printers), hand-held power tools, and vehicles that range from model aircrafts to automobiles.
Within a 3 phase brushless motor the number of teeth (poles) is a multiple of 3 and the number of magnets is a multiple of 2. Depending upon the number of magnets and teeth each motor has a different number of cogging (i.e. magnetic attractions between rotors and stators) steps per turn.