What are the functions of position sensors that only friends who use brushless motors are familiar with? So why use a position sensor? Let's take a look together.
The position sensor plays a role in measuring the rotor position in DC brushless motors, providing correct commutation information for the logic switch circuit, that is, converting the position signal of the rotor magnet into an electrical signal, and then controlling the commutation of the stator winding. There are many types of position sensors with distinctive features, and the three commonly used position sensors for Fuji brand DC brushless motors are electromagnetic position sensors, magnetic proximity sensors, and photoelectric position sensors.
(1) Electromagnetic position sensors are widely used in DC motors, which are open transformers. The open transformer of a three-phase DC motor consists of a stator and a tracking rotor. The stator generally has a spacing of 60 degrees, where the primary windings are connected in series, and the rest are wound with secondary windings WA, WB, WC.
(2) Magnetic position sensor is a semiconductor sensitive component whose electrical parameters vary in a regular manner with the surrounding magnetic field. The basic principles are Hall effect and magnetoresistance effect. Common magnetic sensors include Hall elements or Hall integrated circuits, magnetic resistors, and magnetic tubes.
(3) The photoelectric position sensor adopts the photoelectric effect and consists of components such as a light shielding plate, a fixed light source, and a photovoltaic cell that rotate with the brushless motor rotor.

The above is the answer to why brushless motors need position sensors. You can choose the appropriate method according to actual operational requirements to avoid unnecessary losses caused by blind operation. If you have any other questions, you can follow our website and we will regularly update our website articles, hoping to be helpful to you.
Editor: Lynn