1. Introduction to Halbeck Array
The Halbach array is a magnet structure that was first discovered by American scholar Klaus Halbach in 1979 during electron acceleration experiments. As the structure of this special permanent magnet was gradually improved, the “Halbach” magnet was eventually formed. It uses the arrangement of special magnet units to enhance the field strength in the unit direction. The goal is to generate the strongest magnetic field with the smallest amount of magnets.
The Halbeck array is entirely composed of rare earth permanent magnet materials, and the magnetic field line distribution characteristics of this array are excellent. By arranging permanent magnets with different magnetization directions according to certain rules, the magnetic field lines can be concentrated on one side of the magnet and weakened on the other side. This characteristic allows us to obtain a more powerful unilateral magnetic field in a specific area.
This kind of array is of great significance in engineering. With its excellent magnetic field distribution characteristics, it is widely used in industrial fields such as magnetic resonance imaging (MRI), magnetic levitation, and permanent magnet special motors. By exploiting the properties of Halbach arrays, we can create stronger single-sided magnetic fields using fewer magnets. This greatly reduces the size of the magnetic resonance imaging instrument and the permanent magnet special motor, and reduces the material cost. The other side has less magnetic field, which can prevent objects and people from being exposed to strong magnetic fields.
Overall, the discovery and application of Halbeck arrays had a profound impact on modern industry. The excellent performance and wide range of applications of this array make it an important part of modern industry.
2. Linear Halbach array
The linear Halbach array is the most basic form of Halbach array. This array magnet can be regarded as a combination of radial array and transverse array. In a linear Halbach array, the permanent magnets are arranged in a straight line, and adjacent permanent magnets are magnetized in opposite directions to enhance the magnetic field strength in a certain direction.
At present, linear Halbach arrays are mainly used in linear motors of maglev trains. In maglev trains, linear Halbach arrays are used as magnets to generate propulsion. This magnet structure allows the maglev train to maximize the magnetic field with a smaller amount of magnets and improve the magnetic performance of the levitation system. The other side of the linear Halbach array has less magnetic field, which prevents passengers from being exposed to strong magnetic fields.
3.Circular Halbach Array
The circular Halbach array can be regarded as a linear Halbach array connected end to end.
Among permanent magnet motors, permanent magnet motors using the Halbach array structure have superior performance compared to traditional permanent magnet motors. Due to the special arrangement of the Halbach array, it can generate an air gap magnetic field that is closer to a sinusoidal distribution. And when the amount of permanent magnet material is the same, the air gap magnetic density of the permanent magnet motor using the Halbach array is greater. Because the Halbach array can concentrate the magnetic field in one direction and thereby enhance the magnetic field strength, this high magnetic density magnetic field can significantly increase the output torque of the motor and improve the performance of the motor.
In addition, Halbach circular arrays are also widely used in permanent magnetic bearings, magnetic refrigeration equipment, magnetic resonance and other equipment.
4.How to make a Halbeck array？
① Wipe the contact surface of each magnet block clean and apply special glue on the contact surface. Arrange each magnet piece in order, clamp them with clamps, and wait for the glue to bond the magnets. This method is simple and low-cost, but it is not efficient.
② Directly manufacture a complete magnet, and then magnetize it in a special fixture. This method has high processing efficiency and is relatively easy to achieve mass production. However, it requires a specially designed magnetizing fixture and a magnetizing process, which increases the manufacturing cost.
We hope the content of this article helps you learn more about Halbach Arrays.
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learn more:Fundamentals of Halbach Arrays – YouTube