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Permanent Magnet For Hall Position Sensor in Brushless DC Motor
At present, the applications for brushless DC permanent magnet motors (BLDCMs) in many industries are more and more widely. The major sign to distinguish brushless from brush dc motor is position sensor which is also one of three essential components for the brushless DC motor system. There are lots of position sensors used in brushless DC motors. But hall position sensor is applied more widely because of simple structure, easy & flexible installation and easy to electromechanical integration etc. In a brushless DC permanent magnet motor, hall position sensors (HPS) are mainly used to monitor the electric motor rotor position and rotary speed.
The structure of hall position sensor includes a stator and a rotor like electric motor.
Sensor rotor rotates together with the main rotor of motor to indicate the position of the main rotor. It can directly use the permanent magnet rotor of the electric motor; or additionally install a new permanent magnet rotor in other place of the shaft, generally its pole pairs is designed to be the same with main rotor to increase the average torque and reduce fluctuations in the value of torque. For multi-poles (＞2poles) rotor magnet, bonded NdFeB magnet and ferrite magnet are easy to achieve.
If there are other requirements, such as working temperature, magnetic force, corrosion resistance, customer can select suitable magnet according to the characteristics of each magnetic material. Sintered NdFeB magnet is a high maximum-energy product with acceptable price. Samarium Cobalt magnet is not only high magnetic energy product but good corrosion resistance and temperature characteristics too. AlNiCo is the first generation rare earth magnet with small temperature coefficient, high working temperature and good corrosion resistance. The disadvantage is low magnetic force. Ferrite magnet is the cheapest magnet material. It is weak in magnetic foce, but high stability and don’t need any surface treatment.
China Magnets Source Material Ltd is a professional permanent magnet manufacturer with rich experience on production of hall position sensor magnet. Please contact us by sales@china-magnets-source-material.com if you have any question or enquiry for sensor magnet.
China Magnets Source Material Limited
