The position sensor plays a role in determining the position of the rotor pole in the BLDC motor, and provides correct phase change information for the logic switch circuit. It converts the position signal of the rotor magnetic steel pole into an electrical signal, and then controls the stator winding phase change. There are many kinds of position sensors and each has its own characteristics. There are three kinds of position sensors commonly used in brushless dc motor, namely electromagnetic position sensor, magnetic sensitive position proximity sensor and photoelectric position sensor.

Common overheating causes and treatment methods of brushless DC motor.
1. Overload. Load should be reduced or large capacity motors should be replaced.
2. Local short circuit or grounding of winding, local overheating of motor in light time, burning of insulation in serious time, emitting scorching odor or even smoking. The DC resistance of each phase of the winding should be measured, or the short-circuit point should be found, and the grounding of the winding should be checked by megohmmeter.