China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Motor customers often encounter the problem of permanent magnet demagnetization. What causes this? What are the possible reasons? Today, permanent magnet manufacturer Carichi will discuss the three main causes of permanent magnet demagnetization in actual motor use.
1. Demagnetization caused by the permanent magnet material itself
Material defects: During the manufacturing process of permanent magnets, if the material purity is insufficient or the structure is unstable (e.g., grain alignment issues in neodymium-iron-boron magnets), demagnetization may occur.
Exceeding the magnet's operating temperature: Each type of permanent magnet material has a specific operating temperature range. For example, the commonly used N38SH grade neodymium-iron-boron permanent magnet has a temperature resistance of 150°C. When the temperature exceeds 150°C, demagnetization occurs.
Corrosion and oxidation: Neodymium magnets contain a significant proportion of iron. If the surface is not adequately protected by a coating (such as nickel plating or epoxy resin), it may be affected by oxidation and corrosion, leading to a decrease in magnetic properties.
Hollow cylinder neodymium magnets for high-speed motor rotors
2. Demagnetization caused by motor design
Excessive current: During motor design, if current and voltage are not properly controlled, excessive current flowing through the windings can generate an overly strong magnetic field. This may cause the permanent magnets to operate beyond their capacity, potentially leading to magnetic saturation or demagnetization.
Excessively high temperature: When designing a motor, it is essential to consider the temperature limits of the permanent magnets. If the motor operates in an environment with excessively high temperatures or inadequate heat dissipation, the temperature of the permanent magnets may exceed their safe operating range, leading to magnetic degradation.
3. Demagnetization caused by improper use
High-temperature environment: Prolonged operation in high-temperature environments, especially when there are significant fluctuations in the external temperature of the motor, may cause the permanent magnets to overheat, leading to demagnetization.
External impact: Permanent magnets are highly sensitive to external impacts. Excessive impact, vibration, or collision may cause demagnetization.
Strong magnetic field interference: If the motor is exposed to strong electromagnetic interference sources (such as other high-power motors or high-frequency equipment), this may affect the stability of the permanent magnets and cause demagnetization.
All of the above factors can affect motor performance and even shorten the service life of the motor. Therefore, it is crucial to take appropriate measures to prevent demagnetization during the design, production, and use of motors.
Magnets commonly used in electric motors;
Neodymium arc shaped strong magnets