Magnet manufacturers share: What is multipole ring magnets

 Multipole ring magnets are more ideal for permanent magnet motors and magnetic coupling devices than conventional splicing of multiple arc magnets. They can be divided into isotropic and anisotropic types. The isotropic type generally refers to multipole ring bonded magnets. The anisotropic type, or multipole sintered ring magnet, has been touted as a high-end product.

 

About multipole sintered ring magnets

In the case of sintered neodymium magnets, either radially oriented or multipolar oriented can produce multipolar sintered ring magnets. Radially oriented ring magnets made by radial orientation can be magnetized directly into multipoles along the radial vector. The dominant methods of generating radially oriented magnetic fields include the traditional repulsive and unique Chinese rotational orientation techniques.

 

Multipole sintered ring magnets manufactured by multipole orientation are also called polar anisotropic magnets. A pulse generator coil generates the directional magnetic field of a polar anisotropic magnet. Its magnetic flux lines enter the adjacent S-pole from the N-pole and exhibit a curvilinear distribution. And thus, the magnetic powder also exhibits a curvilinear arrangement. The magnetic field intensity waveform of polar anisotropic magnets is close to a sinusoidal waveform, which is very beneficial for motor applications.

 

Besides the sintering technique, the thermal deformation process is another solution to obtain multipole neodymium ring magnets.

 

Waveform and motor performance

Comparative measurements of multipole ring magnets are mainly characterized by magnetic field strength waveforms, whose parameters such as peak, angle, and cycle duty cycle are closely related to motor performance. The peak indicates the magnet's grade and the degree of saturation of the magnetization. Peak and angular deviations significantly affect motor efficiency, cogging torque, temperature rise, and noise. These two parameters can be modified by optimizing the production process and magnetizing fixtures. In addition, the area and duty cycle affect the electric potential (BEMP), torque rating, and power.

Order high quality magnets, welcome to consult professional custom magnet manufacturers.

 

Reprinted from Haoxiang Magnet - “Magnet manufacturers share: What is multipole ring magnets”