China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Recently, I spoke with a friend who repairs electric motors. Regarding the permanent magnet motors they repair, some customers request that the original demagnetized magnets be remagnetized for reuse, believing this will best preserve the motor’s original performance. We also discussed this issue with magnet manufacturers and would now like to share a summary of the details with you.
Based on the principle of permanent magnet magnetization, it is possible to remagnetize a magnet after it has lost its magnetic properties. However, whether the decline in magnetic performance or complete demagnetization is caused by electrical current or high temperatures, remagnetization cannot restore the magnet to its original level. In other words, the intrinsic magnetic properties have deteriorated and cannot be fully restored. Therefore, when repairing permanent magnet motors, it is generally recommended to replace the magnets with new ones of the same grade.
Arc-shaped ndfeb magnets for electric motors
In particular, demagnetization caused by high temperatures results in more severe magnetic loss. After exposure to high temperatures, the microstructure of the permanent magnet may have changed, leading to partial or complete loss of magnetic properties. Even if remagnetized, its magnetic properties may not fully return to their previous level. From the perspective of the magnetic steel’s mechanical durability, high temperatures may alter the internal crystal lattice structure, making the material more brittle or susceptible to fracture from external impacts. If the original magnetic steel is reused, some pieces may break for various reasons, rendering the repair impossible.
From the perspective of repair cycles and costs, the remagnetization process may require more time and resources, particularly in terms of time and labor, which is clearly not cost-effective for fast-paced production.
Based on the above considerations, it is recommended to replace all permanent magnets when repairing permanent magnet motors.
Other articles on motor magnets;
Effects of Missing Installed Backwards or Weak Magnetism in Motor Magnets
3 Key Inspection Items for Motor Magnets