Magnetic Rotor Assembly and Halbach Array

China Magnets Source Material Limited is a professional manufacturer for permanent magnets, halbach array and magnetic rotor assemblies.

Our magnetic rotor assemblies feature precision and complex, including a wide variety of permanent magnets:

1. Samarium Cobalt (SmCo)
2. Neodymium Iron Boron
3. Ferrite
4. AlNiCo

Halbach array structure is one of rotor assemblies we made for customer worldwide.

What is halbach array? Description from Wikipedia: A Halbach array is a special arrangement of permanent magnets that augments the magnetic field on one side of the array while cancelling the field to near zero on the other side.

At present, the permanent magnet motor is developing toward high power, high function and miniaturization. The high power density and high efficiency are the common requirements for all types of permanent magnet motor design.

According to principle of 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.

For permanent magnet motor, generally, there are two measures to increase air gap flux density in 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

Halbach array is a new type of permanent magnet arrangement combined with 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 rotor or outer rotor of the external permanent magnet.

In brief, its application in the permanent magnet motor has great advantages:

1. Sine wave of air-gap magnetic field
2. Good magnetic shielding effect
3. High power density
4. Light weight
5. Small in size

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

China Magnets Source Material Limited has a wealth of experience in permanent magnet industry over 20 year. Please feel free to contact us if you need permanent magnets, halbach array magnets or motor rotor assembly.

We know how to:

1. Select the right magnets
2. Choose the suitable coating
3. Design optimization
4. Magnet production
5. Assembling components

House Uses of Magnets: 55 Amazing Neodymium Magnets Applications in Daily Life

When it comes to house uses of magnets, I’m sure you've seen enough about fridge magnets on instagram. If you're looking for some different magnet applications that you can use at home today, then you'll love this share.

Except for refrigerator magnet – soft magnet, there are several hard magnets used in daily life like toy bucky ball andmagnetic bracelets. These are also called rare earth magnets as they use elements such as neodymium andsamarium that are classified as rare earth metals. They are small but very powerful, thus they can attract objects many times heavier than themselves.

Neodymium magnet is one type of rare earth magnets which can be seen in many daily goods including headset, guitars, speakers, cordless tools and even hybrid vehicles. There is an infographic from first4magnets that can help you to get a clear idea for this. 

Also below is a list of 55 amazing neodymium magnets household applications that you can easily implement at your home. Whether you’re a student, worker, housewife or DIY enthusiast, there’s bound to be something here that will fit for your application.

Browse by Category: Click any of the links below to jump to each category.

1. Magnetic Tools
2. Magnetic Storage
3. Magnetic Toy and Education
4. Magnetic Decoration
5. Magnetic Levitation
6. Life Tips with Magnet

Click here to read more

Can Rare Earth Magnets Work with Art Installations?

Permanent magnet is applied to many products including toy, speaker, sensor, jewelry, teaching, guitar, aquarium, electric tool, medical treatment and even motor in hybrid vehicles. One of major application in daily life is that neodymium magnets are often chosen as the mounting solution for use to hold everything from keys to clothes. Based on this, people in art museum begin considering hanging art objects with magnets.

Art installation or art conservation is a technical process that requires a lot of knowledge of the material for both art and mountings. Especially to hang textiles, linens or paintings, utilizing straight pins will destroy them. But with magnets, there will be no damaging. Now super-strong rare earth magnet is becoming a common tool to mount, store, and treat artifacts. Pot magnet with hook and small block or disc neodymium rare-earth magnets are often used here.

Forart quickly installed, saving time and money, China Magnets Source Material Ltdoffers high quality strong magnet for museum. Contact us to learn how we can help your magnet mounts.

Rare Earth Magnet for Magnetic Drive Pump

Magnetic Drive Pump solved work under corrosive, inflammable, explosive, toxic, leakage, and clean liquid environment. Permanent magnet in the magnetic drive pump refers to coupling magnet. Magnetic drive pump makes full use of performance of magnetic force on ferrous material and non-ferrous material.

The first generation magnet on pump magnet is ferrite magnet. It’s cheap and wide source. Due to poor magnetic performance, it limits the development of magnetic drive pump. The second generation magnet is samarium cobalt magnet and AlNiCo magnet. These two materials are better than ferrite, and let magnetic drive pump achieve large torque. But their cost is very high because material samarium and cobalt which used in smco and alnico are rare and strategic resource. It also restricts pump development. The third generation Sintered NdFeB magnet with (BH)max 207 kJ/m³ to 422 kJ/m³ is an ideal material for magnetic drive pump. Sintered NdfeB magnet is the strongest magnet which can reduce the volume of pump and its material Fe and Nd is rich than samarium, so price is affordable. It helps magnetic drive pump get the market finally.

China Magnets Source Material Limited is able to manufacture different kinds of high performance magnets for magnetic drive pumps. You are welcome to contact us for more information. Our engineers also are ready to provide technical assistance.

Permanent Magnet of The Magnetic Flux Leakage (MFL) Magnetizing Device for Oil Pipeline

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

The Magnetic Flux Leakage (MFL) of  non-destructive inspections is the most widely used detection method to detect a variety of flaws in oil or gas pipeline. The MFL system consists of magnetizing device, yoke and hall sensors. Its working principle is (as below drawing): firstly, to magnetize pipeline detection range by strong magnetic force from magnetizing device. The leakage magnetic field will appear when there is flaw on the pipeline wall. Secondly, to convert MFL signal collected by hall sensors into current to test the flaw size and location.

 

 

Magnetizing is the first step for MFL and determines whether pipeline test area can produce enough magnetic field signals. Magnetizing device usually uses permanent magnet, such as ferrite,alnico, smco and ndfeb magnet, due to its different characteristics in high magnetic energy product, small volume, light weight and no external power required. Ferrite (ceramic) is cheap but low Br; AlNiCo is high Br but low coercive force; rare earth magnet which includes samarium cobalt and neodymium iron boron is high coercive force and remanence but expensive.

For different permanent magnets, the magnetic circuit should be designed according to their magnetic properties, give full play to its advantages, so that the magnetic circuit reaches to the optimum. For high remanence and low coercivity magnetic material, it should adopt an elongated magnet; but on the contrary, it should adopt stubby magnets. If the magnetization effect cannot meet the requirements and coercivity cannot increase, increasing the size of the permanent magnets (typically width and thickness) can meet the requirement. Common grades for MFL magnet are N38, N42,N45 and N50M, sizes 40x20x10mm, 25x25x25mm, 40x25x10mm and 45x45x45mm and soon. We also manufacture arc (segment), ring, and cylinder type magnet formagnetic flux leakage testing.

 

 

China Magnets Source Material Ltd. hasmany years production experience for MFL magnets; the magnets have been appliedfor the detection of the Pacific seabed pipeline. If you have such requirement, please feel free to contact us.

8 Factors to Affect the Magnetic Force of Permanent Magnet

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

The magnetic force for permanent magnet can stay for a long time but it is not really permanent. There are 8 factors which will affect magnetic force.
1. The material formulation
Material formulation limits magnetic properties fundamentally. Sintered ndfeb magnet is the strongest and alnico is the weakest. There is also difference for the same material based on formulation. The magnetic force for grade N45 is higher than grade N35 for the same size magnet.
2. Magnet size and shape
3. The magnetization saturability
Only when full charged, magnetic force can be achieved completely.
4. Design of magnetic circuit
Different magnetized direction, the magnetic force is different. For a cylinder magnet, magnetic force by axial-magnetized is stronger than diameter-magnetized.
5. Working temperature
Magnet is very sensitive to working temperature, especially for sintered ndfeb magnet. The momentary and continuous highest temperature of environment may cause certain demagnetization including recoverable and unrecoverable, reversible and irreversible. According to working temperature range 80-200 celsius, sintered ndfeb magnet is divided into several grade series (N, M, H, SH, UH, AH etc.). The cost will be expensive for high working temperature grade. So you need to consider your working temperature and choose the right grade. The loss of magnetic force can be ignored under working temperature permitted range. But magnetic force will decrease rapidly while working under a limit working temperature for a long time.
6. Working humidity
Sintered ndfeb magnet is easy to be oxidized and then loss its magnetic force. We use coating to avoid this problem. But this is not a permanent solution. So the dryer, the better.
7. External magnetic field
Magnetic force will reduce while placing opposite poles around magnet, only when the magnetic field of opposite poles is several times larger than magnet itself, the reduction will be evident.
8. Strong shock
It will reduce magnetic force, but needs long time.

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.

Magnetic Property Parameter transformation by china-magnets-source-material.com

Description	Abbreviation	Unit SI	Unit CGS	CGS / SI
Remanence	Br	T	kGs	10
Coercive force	Hcb	KA/m	kOe	4π/10³
Intrinsic coercive field	Hcj,Hic	KA/m	kOe	4π/10³
Magnetic energy product	BH max	KJ/m³	MGOe	4π/10³
Magnetic force on Surface	H	KA/m	kOe	4π/10³
Magnetic flow	φ	Wb, Vs	Mx	108
Magnetic moment	Mm	A.m ²	Vs.cm	10³
Magnetization intensity	M	T	kGs	10

Note: Gs and Oe are the same numerical value, but two different physical significance units. So the magnetic field is the same by 1 Gs and 1 Oe.

10³/4π=79.6

Machining Methods for Permanent Magnet by china-magnets-source-material.com

Slice – to cut raw material from big into small, it is on direction of plane

Wire-electrode cutting – to cut raw material from big into small, it is for curved face machining and big size plane

 

Surface Grinding – to grind plane for high dimensional precision

Forming grinding – to process curved face which has high requirement for precision

 

Ultrasonic drilling – to process small hole

 

Trepan boring – to process large hole

Chamfering – to process the sharp corner of product into round or bevel angle.

Permanent Magnet Dimension Parameter by china-magnets-source-material.com

Basic size: length, width, height, diameter, radius

 

Chamfer size: corner radius and 45°

 

Size tolerance: the amount of variation permitted in a given dimension

 

Shape tolerance: straightness, flatness, roundness, cylindricity, profile of a line and profile of a surface

 

Position tolerance: Parallelism, perpendicularity, lean, concentricity, symmetry, position, degrees, circle run-out and total run-out

The thickness of surface treatment: the thickness of NiCuNi or black epoxy

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)