The magnetic performance attenuation of multipole ceiling fan magnet is directly related to the intrinsic stability of the material and the engineering protection system. As a key component of permanent magnet synchronous motor, this component is formed by anisotropic sintering process using rare earth permanent magnet material. Its magnetic retention ability depends on the thermodynamic stability of the grain boundary diffusion phase. The columnar crystal structure formed by high-temperature solution treatment suppresses spontaneous demagnetization through the pinning effect of magnetic domain walls. The electron spin coupling of rare earth elements enhances the magnetocrystalline anisotropy field and reduces the probability of magnetic moment deflection caused by thermal disturbance.
The multipole topology in the magnetic circuit design of multipole ceiling fan magnet shortens the leakage magnetic area through the closed path of magnetic flux, reducing the loss of the intrinsic coercive force of the material by the stray field. The gradient-oriented multipole ceiling fan magnet arrangement optimizes the magnetic field distribution in the working air gap and avoids irreversible demagnetization caused by local overload. The packaging process constructs a metallized protective layer on the surface of the magnet to block the penetration path of oxygen and moisture and prevent the extension of micro cracks caused by hydrogen embrittlement.
The change of magnetic properties of multipole ceiling fan magnet in long-term operation is affected by the coupling of alternating electromagnetic field and mechanical vibration. The internal stress release of magnet is realized by elastic deformation rather than magnetic domain rearrangement, maintaining the stability of residual magnetic density. The safety margin design of the material Curie temperature and the temperature difference of the working environment ensures that the ferrite or NdFeB matrix does not trigger phase change demagnetization under temperature rise conditions.
