Permanent Magnet for Motor

China-Magnets-Source-Material.com | Best Magnetic Solution

Permanent magnet for motor is one of important and high-end applications. In order to achieve optimal performance of PM motor, motor designers need to continually change their design and find best material for motor. Several factors will affect the choice of motor magnet.

1. Magnetic Material: Sintered NdFeB, Bonded NdFeB, Ferrite, SmCo, AlNiCo

• Sintered NdFeB magnet has high magnetic performance (including high magnetic flux, remanence, coercive force, resistance to magnetic demagnetization, and low temperature coefficient, loss of irreversible). It can improve motor performance and reduce the volume as well. It is main magnet material for PM motor.
• Bonded NdFeB magnet is well known for good plasticity. It suits for complex shape magnet or magnet with multipole magnetization direction. Usually, mould is needed for its production.
• Ferrite is an old magnet material which used on PM motor. It’s heavy weight but cheap price.
• SmCo can work under high working temperature. The magnetic force is weaker than Sintered NdFeB magnet, but also very powerful.
• AlNiCo with very high working temperature 450-550℃ is the oldest magnet material for motor and replace by ferrite later.

2. Magnet Max. Working Temperature: Sintered NdFeB magnet 150℃ (N35SH, N38SH, N42SH, N45SH), 180℃ (N35UH, N38UH, N40UH) , 200℃ (N35EH, N38EH); Sm2Co17 300℃

 

3. Magnet Working Environment: low weight loss (high corrosion resistance)

 

4. Magnet Coating: NiCuNi, Zn, Black epoxy, Grey epoxy etc. To make full use of magnet performance and control tolerance well, sometimes the plating of magnet uses phosphorization or passivated for temporary protection

 

5. Magnet Shape: segment (arc), wedge, bread, block, ring, or special shape

 

6. Magnetized direction: it depends on magnet design. In order to get best performance, magnetic declination can’t be ignored.

 

7. Magnet tolerance: a lot of motor magnets are made of segment magnets, and small tolerance is very important to reduce air gap and assemble a ring.



Segment NdFeB Magnet For Motor

China Magnets Soure Material Limited is rich in experience of motor magnet manufacture, such as magnet for flat brushless motor, DC Motor, AC motor, stepper motor , servo motor, synchronous motor; magnet for mini motor or special motor; magnet for high temperature to high humidity; magnet for regular shape or irregular shape.

You are welcome to contact us for more information. Our engineers also are ready to provide technical assistance.

How to choose a magnetic material? By china-magnets-source-material.com

When choose a magnet material, you need to figure out the requirement you need magnet to do in your application, but not blindly pursue high performance magnetic material; and then get a comprehensive understanding of different magnetic materials. If you have confusion on some point, you can ask for technical help from magnet specialist or manufacturer.

Material	Magnetic Property	Working Temperature	Corrosion Resistance	Price	Remark
NdFeB Magnet	high	low	low	high	1
Ferrite / Ceramic	middle	middle	high	low	3
SmCo Magnet	high	high	high	high	2
AlNiCo Magnet	low	high	high	middle	4

Ferrite and ndfeb magnet can be processed by sintering or bonding method. The Sintered magnet has high magnetic force, but poor formation. The bonded magnet has good formation, but low property.
Alnico can be processed by casting and sintering, the cast alnico has high property, but poor formation. The bonded alnico has good formation, but low property.

This is a brief introduction for choosing magnetic material, for more information, please visit our website www.china-magnets-source-material.com

The magnetic field orientation for permanent magnet by china-magnets-source-material.com

Orientation direction: The direction where anisotropic magnets can obtain the best magnetic property.

Permanent magnets are divided into two types: Isotropic and Anisotropic.

Isotropic magnet: The magnet has same magnetic property in any direction.

Anisotropic magnet: The magnet has different magnetic property in different direction. And there is one orientation which can obtain the best magnetic property.

Sintered NdFeB magnet is anisotropic magnet. So the orientation (magnetized direction) should be decided before production.

Bonded NdFeB magnet is Isotropic magnet. If you buy uncharged magnet, there is no necessary to confirm magnetization direction.

What is magnetic material? by china-magnets-source-material.com

Magnetic material is one of three fundamental functional materials in the industry. 

It was divided in two types based on magnetic properties: soft magnet and hard magnet (also named permanent magnet). Both are easy to get magnetized. The difference is: hard magnet can stay magnetized for long time with high coercive force; soft magnet has low coercive force, so lost its magnetic force easily.

Soft magnet: steel and iron, soft ferrite and high iron amorphous materials

Hard magnet: Sintered Neodymium Magnet, BondedNeodymium Magnet, AlNiCo, Samarium Cobalt Magnet, Ferrite (due to rare earth material content, they are also called rare earth magnets except ferrite)