How to Use Halbach Array

A Halbach array is a special arrangement of permanent magnets that augments the magnetic field on one side of the array while canceling the field to near zero on the other side. This is achieved by having a spatially rotating pattern of magnetization.

The rotating pattern of permanent magnets (on the front face; on the left, up, right, down) can be continued indefinitely and have the same effect. The effect of this arrangement is roughly similar to many horseshoe magnets placed adjacent to each other, with similar poles touching.Halbach array

1. Materials
Magnet: Neodymium Magnet
Hardware part: 20# steel, martensitic stainless steel

2. Application
Linear Halbach arrays:
Such as the brushless AC motor, voice coils, magnetic drug targeting to high-tech applications such as wiggler magnets which are used in Particle accelerators and Free-electron lasers.
Halbach cylinder:
Such as brushless AC motors, magnetic couplings, and high field cylinders. Both brushless motors and coupling devices use multiple field arrangements.

neodymium magnet halbach

Halbach arrays are widely used in magnet rotors. Rare-earth permanent magnet motor is a new type of permanent magnet rotor, it began in the early 70s. And the rare-earth permanent magnet motor has a series of advantages, such as small size, light weight, high efficiency, and good characteristics. Its applications are very extensive and extend all over fields of aviation, space, defense, equipment manufacturing, industrial and agricultural production, and daily life.

Halbach arrays can be made by neo magnets. Sintered NdFeB magnet is one of the high-performance rare earth magnets, with high remanence, high coercive force, high energy product and high performance/cost ratio, It is easily produced into various sizes.

Sintered NdFeB magnets are widely used in high performance stepper, DC motors, servo motors, and linear motors, actuators, loudspeakers, headphones, electronic instruments, switches, relays, magnetic imaging for medical and geophysical applications, holding systems, magnetic bearings, magnetic couplings, hard disk drives, magnetic separator, magnetic lifter, other magnetic tools and so on.

For more information, please visit https://www.stanfordmagnets.com/

What is Halbach Array Motor

Halbach array is a new type of permanent magnet arrangement combined with the radial and tangential array, which can increase the magnetic field on one side of and weakened the magnetic field on the other side.
Using Halbach array in permanent magnet motor can increase the magnetic flux in the air gap and decrease the magnetic flux in the rotor yoke, and it is most suitable for the inner or outer rotor of the external permanent magnet.
At present, the permanent magnet motor is developing toward high power, high function, and miniaturization. The high power density and high efficiency are the basic requirements for all types of permanent magnet motor design.
According to the principle of magnet motor design, the increase of magnetic loading is to increase the motor gap magnetic flux density, which can reduce motor size and improve the power density.

Halbach array motor

For permanent magnet motor, generally, there are two measures to increase air gap flux density in the motor.
1. Change magnetic material: try to use permanent rare earth magnet with higher residual magnetic flux density. But restricted by magnet material performance and price, the actual alternatives are few.
2. Change magnet structure and arrangement

In brief, its application in the permanent magnet motor has great advantages:
1. The sine wave of air-gap magnetic field
2. Good magnetic shielding effect
3. High power density
4. Lightweight
5. Small in size

Neodymium magnets play a very important role in the renewable energy market. So we believe this magnet motor could find a broad range of industrial and automation applications, from electric vehicles, aerospace, independent power generation to other occasions.

The magnetic rotor assemblies are complex, including a wide variety of permanent magnets:
1. Samarium Cobalt (SmCo)
2. Neodymium Iron Boron
3. Ferrite
4. AlNiCo

Halbach Array For Magnetic Bearings

Klaus Halbach has been investigating novel designs for permanent magnet arrays for many years, he used advanced analytical approaches to employ a keen insight into such systems. One of his motivations for this research was to find more efficient means for the utilization of permanent magnets for use in particle accelerators and in the control of particle beams.

radial Halbach magnetic bearing rotor

As a result of his pioneering work, high power free electron laser systems, such as the ones built at the Lawrence Livermore Laboratory, became feasible, and his arrays have been incorporated into other particle focusing systems of various types. This paper reports another, quite different, application of Klaus’ work, in the design of high power, high efficiency, electric generators and motors.

When tested, these magnet motor or generator systems display some rather remarkable properties. Their success derives from the special properties which these arrays, which we choose to call “Halbach arrays,” possess.

Halbach-arrays are widely used in the passive magnetic bearings. The nowadays industrial rotor machines are more flexible and often operating with ultra-high speed. Using the passive magnetic bearings in certain applications, we need to take into account the occurrence of radial component in the case of axial bearings and axial component in the case of radial bearings.

Journal bearings, in addition to passing load forces of the rotor, rotor weight and damping must take into account the existence and impact of this negative component forces. Therefore, in the design of passive bearings Halbach-arrays are introduced.

Halbach array is a special setup and configuration of permanent magnets so that you can get the concentration of magnetic flux in a specific, desired item, and remove it from less important or unwanted places.

Among the Halbach arrays, to guide the magnetic field in the desired way, we can distinguish boards between 180° and 90°. These terms relate to the relationship between the magnetization vectors.

Halbach magnetic bearing rotor

In the construction of the passive radial magnetic bearing 180° Halbach-array was used. This kind of magnetic bearings belongs to the repulsive magnetic bearings.

The examined passive magnetic bearing is composed of four pairs of the neodymium-iron-boron (NdFeB) magnets rings. These rings are axially magnetized, which means that magnetic poles are placed on the flat circle sides of the magnets.

The introduction of the Halbach-arrays allows the adequate orientation of the magnetic field in the placenta, and to reduce the negative impact of the active component forces. The use of Halbach-arrays and magnetic bearings, allow to develop and to implement the high performance passive magnetic bearings.