Treatment methods for demagnetization and stabilization of permanent magnets

Treatment methods for demagnetization and stabilization of permanent magnets

The permanent magnet auxiliary exciter is different from the general AC exciter, so it is a Do not disassemble and assemble at will, otherwise there will be a risk of loss of magnetism due to disassembly and assembly. Especially when the structure is not well understood, and the necessary technical precautions, safety protection measures and necessary process equipment are not taken, rashly disassembling or assembling will not only damage the motor, but also cause damage to the motor due to operational errors and carelessness. resulting in personal accidents.

Aiming at the demagnetization factors of permanent magnets, put forward the corresponding technical requirements for magnetic properties to the permanent magnet material manufacturing unit. However, the mistakes and carelessness of the motor manufacturing unit in the process of storing and assembling the permanent magnets will also cause artificial loss of magnetism. Because the permanent magnet is used as the constant magnetic energy source for the excitation of the permanent magnet auxiliary exciter, it is required to absolutely ensure that the magnetic circuits at the ends of the N pole and the S pole of the permanent magnet cannot be short-circuited to form a magnetic short circuit in the structural design and under any conditions, otherwise it must be Will cause artificial demagnetization of permanent magnets.

But how to stabilize the magnetism and what method to use to stabilize the magnetism, as well as the way and times of magnetism stabilization, must be determined according to the permanent magnet material selected for design.

The method of permanent magnet magnetic stabilization treatment: there are two processing methods: sudden short circuit magnetic stabilization and air magnetic stabilization. It is worth emphasizing to the designer that no matter what kind of magnetic stabilization treatment method is used in the design, the type test of the permanent magnet auxiliary exciter must be carried out in accordance with the industry standard JB/T9578 "Technical Conditions for Rare Earth Permanent Magnet Synchronous Generators". After the short-circuit test, the performance of the product must meet the national and industry standards and design requirements.

Magnetic performance test of permanent magnet inspection sample

The magnetic performance test of the permanent magnet inspection sample is mostly performed with a pulsed magnetic field with a strength of 400kA/m or more for saturation and magnetization. The device for generating the pulsed magnetic field includes a thyristor control method and a capacitor discharge method.