BLDC motors use electronic instead of mechanical commutation to control the power distribution to the motor. Latching Hall-effect sensors, mounted in the motor, are used to measure the motor’s position, which is communicated to the electronic controller to spin the motor at the right time and right orientation. These Halleffect sensors are operated by a magnetic field from a permanent magnet or an electromagnet, responding to South (operate) and North (release) poles. These magnetic sensors determine when the current should be applied to the motor coils to make the magnets rotate at the right orientation.
There are several design characteristics that BLDC motor manufacturers should evaluate when selecting a bipolar latching Hall-effect sensor to commutate the motor so it can operate as efficiently as possible. These include sensitivity, repeatability, stability-over-temperature, and response time.