Analysis of Demagnetization Phenomenon
The demagnetization phenomenon of Motor Magnets is usually caused by a variety of factors. First, high temperature is one of the key factors leading to demagnetization. When the motor is running, the current generates heat through the winding. If the heat dissipation is poor and the ambient temperature of the magnet is too high, the orderly arrangement of the magnetic domains inside the magnet will be destroyed, thereby reducing the magnetism. For example, in some industrial motors that run at high load for a long time, if there is a lack of an effective cooling system, the magnets are easily demagnetized due to overheating. Secondly, the interference of strong external magnetic fields may also cause demagnetization. When the motor is in a strong electromagnetic interference environment, the external magnetic field interacts with the magnetic field of the Motor Magnets, which may disrupt the magnetic domain structure inside the magnet and cause the magnetism to weaken. In addition, excessive mechanical stress, such as vibration and impact generated by the motor during high-speed operation or frequent start-stop, will cause micro cracks or structural deformation inside the magnet, thereby affecting its magnetic properties and causing demagnetization.
Material selection and optimization
In terms of optimizing anti-demagnetization performance, the selection of materials is crucial. Rare earth permanent magnet materials such as neodymium iron boron (NdFeB) have high magnetic properties, but relatively speaking, their anti-demagnetization ability is insufficient at high temperatures. By adding specific trace elements, such as heavy rare earth elements such as dysprosium (Dy) and terbium (Tb), their coercivity can be significantly improved and their anti-demagnetization performance can be enhanced. However, heavy rare earth element resources are scarce and expensive, so some new permanent magnet materials with no heavy rare earth or low heavy rare earth content are also being developed. For example, by optimizing the microstructure and manufacturing process of NdFeB and using technologies such as grain boundary diffusion, a small amount of heavy rare earth elements can be enriched at the grain boundaries, which can effectively improve the anti-demagnetization performance and reduce the amount of heavy rare earth. In addition, although some ferrite permanent magnet materials have relatively low magnetic properties, they have good temperature stability and anti-demagnetization performance, and they also have certain advantages in some motor applications that do not require particularly high magnetic properties but have a relatively harsh environment.
Structural design and protection
Reasonable structural design helps to improve the anti-demagnetization ability of Motor Magnets. For tile-shaped magnets, a block structure can be used to increase the complexity of the magnetic circuit, improve the stability of the magnetic field, and reduce the impact of local demagnetization on the overall performance. In the overall structural design of the motor, adding a magnetic shielding device can effectively block the interference of external strong magnetic fields and protect Motor Magnets. For example, in some precision motors or motors working in a strong electromagnetic environment, a shielding cover made of metal materials with high magnetic permeability is used to wrap the magnets, making it difficult for the external magnetic field to penetrate. At the same time, optimize the heat dissipation structure of the motor to ensure that the magnets work within a suitable temperature range, such as using efficient cooling fans, heat sinks or liquid cooling systems, etc., to reduce the risk of demagnetization due to high temperature.
Magnetization and use management
The correct magnetization process also has an important impact on the performance of Motor Magnets. During the magnetization process, it is necessary to ensure that the magnetization field strength is sufficient and uniform, so that the magnets reach the optimal magnetic saturation state, thereby improving their initial magnetic properties and anti-demagnetization ability. During the use of the motor, it is necessary to avoid overloading the motor, because overload will cause excessive current, generate excessive heat, and accelerate the demagnetization of the magnets. Regularly maintain and inspect the motor to promptly detect the demagnetization of the magnet and take appropriate measures according to the degree of demagnetization, such as adjusting the motor operating parameters or replacing the magnet. In addition, during the storage and transportation of the motor, care should be taken to prevent the magnet from being affected by adverse factors such as high temperature, strong magnetic field and mechanical shock to ensure the stability of its performance.
