What is A Magnet Rotor Made of

Magnetic motor rotor is formed by magnetic steel, metal shaft or metal shell. According to detailed application situation, the rotor magnet can be sintered, molded or injection molded with NdFeB magnet material and Ferrite magnet material with multi-poles magnetic rings. It can be used for the high-speed motor, line motor, stepper motor, etc.

With the increasing performance of permanent magnet materials, rare earth permanent magnet materials are widely used in electrical fields. Using high-performance rare earth permanent magnet materials to make a motor, the structure does not require special electrical excitation system, which helps to improve motor efficiency and power factor, and save energy, reduce the size of the motor.

magnets rotor
Currently, in the design of permanent magnet motor, the general assumption that a uniform distribution of the various parts of the magnetic field of the permanent magnet and the magnetic properties of the same batch of permanent magnets can be the same, while the need to use a permanent magnet demagnetization curve of permanent magnet at room temperature under suppliers, intrinsic connectivity magnetic parameters, residual magnetism, such as density and maximum energy product.

However, since the manufacturing process and the level of the plant and other reasons, there is a temperature in each portion of a permanent magnet hereinafter actual performance differences and the performance of the same group of permanent magnets is different.

The magnetic properties of the permanent magnet

permanent magnet motor in normal operation can be closely related to the magnetic rotor, permanent magnet motor can directly determine whether reliable operation.

When the permanent magnet motor is running, sometimes leaving the rotor temperature higher NdFeB irreversible demagnetization phenomenon, causing permanent magnet synchronous motor efficiency and power factor and other performance indicators deteriorated.

Furthermore, a permanent magnet motor rotor can be customized by different kinds of magnetic materials, and custom drawing is welcomed.

How to Recycle Magnets

The magnet made from rare earth is not a new technology. It was developed by scientists as early as 1982. Its official name is “NdFeB strong magnet”. The method is to extract Nd, Fe, and B from rare earth to form the metal body and then turn on current to magnetize.

The neodymium magnet is the most powerful magnet at present, and the loss of magnetic force is very slow, almost reaching the effect of the permanent magnet. Neodymium magnets are now widely used in computer hard drives, Halbach array, mobile phones, eardrums, speakers, and battery-powered electronic products.

Recycle Magnets

Turning old into new

Permanent magnets recycle means the extracting the rare earth elements from the magnets again. However, it is very hard and expensive.

The scientists of the Fraunhofer Project Group for Materials Recycling and Resource Strategies IWKS in Alzenau and Hanau of the Fraunhofer Institute for Silicate Research ISC are now pursuing a different approach to recycle the entire material instead of trying to regain each individual type of rare earth.

Because the composition of the material is already almost as it should be, this process only needs a few steps, and this is much easier and more efficient.

The first magnet successfully recycled
The scientists rely on the melt spinning process that already tried and tested for other alloys, also known as “rapid solidification”. The details are as below:
The researchers liquefy the magnet in a melting pot. The liquefied material, heated to more than 1000 degrees Celsius, is directed via a nozzle onto a water-cooled copper wheel that rotates at a speed of 10 to 35 meters per second. As soon as the melted droplet comes into contact with the copper, it transfers its heat to the metal within fractions of a second and solidifies.
The scientists call the emerging material formations “flakes”. The special feature is the structure formed inside the flakes. If the melted material were allowed to solidify in the normal way, the atoms would “line up in rows” in a crystal lattice. In the melt spinning procedure, however, crystallization is avoided: Either an amorphous structure is formed, in which the atoms are completely irregularly arranged, or a nanocrystalline structure, in which the atoms arrange themselves in nanometer-sized grains to form a crystalline structure.
The advantage: The grain sizes – meaning the areas with the same crystalline structure – can be specifically varied. They can be used to change the properties of the permanent magnet. In a further step, the researchers mill the flakes into a powder, which can then be further processed. “We press it into its final shape”, Diehl says

If the price of rare earth elements continues to go up, magnet recycling will be more cost-efficient and recycling permanent magnets from wind turbines and electric motors will be popular.

Now they have already set up a demonstration plant and have managed to recycle magnets there. This demo system can process up to half a kilogram of molten material and is somewhere between a lab and a large-scale plant.

In many cases, the rare earth magnets are extremely difficult to remove from the engines. So the potential ways of creating a collection cycle for used engines, and also of a design more suitable for disassembly is what the scientists want to develop.

NdFeB Magnet on New Energy Automobile

High-performance of rare earth magnet refers to high magnetic energy products or combination property of the coercivity & magnetic energy products in the conventional sense. Currently, the development degree of the high-property rare earth magnet is influenced by the demand of the application industry.

SmCo magnet and NdFeB magnet both belong to rare earth magnet family because of the Sm, Co, Nd, B, Dy, Ga elements in their composition. They are the strongest type of permanent magnets available, producing significantly stronger magnetic fields than other types such as ferrite or alnico magnets, for SmCo has magnetic energy product about 15 – 30MGOe and sintered neodymium magnet has about 27- 50MGOe.

The constantly upgraded motors in the new era ask higher coercive force. So the higher working temperature and coercive force can ensure the strong ability of anti-demagnetization. For example, because of high transient load, the drive motor in the new energy automobile have the critical requirement on the magnet coercive force.

New Energy Automobile

Is the high corrosion magnet the future research direction?

To ensure that the electric car can still run after going through more than 20 kilometers cold summer heat, there are many aspects need to research, such as magnetic property, relative physical performance and reliability working life. So in the premise of guarantee the basic magnetic performance, to prolong rare earth magnet’s using life is one of the current and future permanent magnet development direction.

What are product homogeneity and the relationship with magnetic declination?

Magnet module homogeneity is related to the current stability when the motor output. With bad homogeneity, distribute unevenly magnetic field will cause motor vibration. There are lots of influence factor caused magnetic declination; one is homogeneous materials, the other is uniform magnetization, and some process like magnet perpendicularity is also a factor.

What is the highest working temperature for sintered neodymium magnet?

At moment, no neodymium magnet can meet 300℃ working temp. Actually, the working temp. of neodymium magnet depends on its operating environment. Take the drive motor in the new energy automobile for example again, the heat resistance requirement of this drive motor magnet, whether 180℃ or 200℃, rests with the power of the engine. And in actual production, it’s necessary to leave some space to keep its temperature stability by choosing higher working temp magnet than originally working temperature. By this reason, some company will request 220℃ magnet.

Which magnet performance has an impact on motor power and speed?

It’s a simple structure, small volume, lightweight, low loss and high efficiency of rare earth permanent magnet rotor. So motor power speed is often about magnetic force.

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


What are The Features of Adhesive Magnets

Adhesive magnets refer to 3M double-side adhesive NdFeB magnet. This magnet is usually used on box, purses, displays, electronic products and DIY household gadgets etc.

With the help of magnetic force and adhesive force, the 3M adhesive magnet is an idea link to the ferrous and nonferrous object.

It contains three parts: sintered NdFeB magnet (disc, block, oval or based on your design), adhesive (foam tape VHB4945, 467MP, 468MP etc.) and liner.

3M super strong ndefb adhesive magnet

The coating on the magnetic side can be glossy or matte, self-adhesive on nonmagnetic side

Neodymium magnet raw materials are widely used in the industrial field, such as a speaker, louder speaker, sensor, motor, alternator etc; And also it is popular in ladies bags, purses, shoes, crafts, and jewelry etc.

A magnet for badges fastener provides a professional way of displaying name badges and identification without damaging your clothing. Magnetic name badge holder is with a strong magnet and metal molded, which allows the tag to be easily clipped onto your shirt or suit without the damaging effects of pins or clips.

Magnetic name tags are perfect for suits or expensive clothing which you may like very much and you don’t want to be damaged. With strong permanent neodymium magnets attached, the magnetic id badge holder can be used over and over again, therefore it is also called a reusable magnetic name badge.

The Features of Adhesive magnets:
1. Ideal for professional or hospitality settings.
2. Additional fastener options including strap clips, lanyards, and magnetic are available.
3. Pocket badges do not need a fastener.
4. Available in multiple sizes and shapes.
5. Includes pin or swivel clip fastener.
6. Rectangle metal name badges come with square corners.

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