Arc Segments Permanent Magnets – the Most Popular High-Performance Motor Magnets Solutions

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1. Aadvantages of Segment Arc Motor Magnet
2. The Performance of Magnetic Segment Impact on Motor
3. How to Choose Motor Segment Material?
4. Permanent Magnet: the Core of PM Motor
5. How to Join Neodymium Magnet Arcs Into a Radially Ring?
6. Motor Magnet Customized Service

We recently highlighted radially magnetized ring magnet for micro motor rotor in our previous blog. However, this does not mean that the traditional arc segment motor magnet will disappear gradually.Segment motor magnet has advantages of easy manufacture and low cost compared with radial magnet ring. It’s still the most common motor magnet shape, especially for PM DC motor.

1. Compared with electro-magnetic, we can list more advantages of segment arc motor magnet:

1. Simplify the structure of motor
2. Easy maintenance
3. Light weight
4. Small volume
5. Operational reliability
6. low energy consumption

2. The performance of magnetic segment impact on motor or generator:

1. Br (residual magnetic flux density): high Br can ensure that the motor has a high speed, high torque and high output power. Then the motor will have a high efficiency. Such as for starter motor, high Br magnet arc will provide high instantaneous start-up force.
2. Hcb: high Hcb can provide enough electromotive force needed for motor output, making the operating point of motor close to the maximum energy product to take full use of magnetic property.
3. Hcj: high Hcj can ensure there is a strong resistance against the demagnetization caused by motor overload, against the anti-aging, and against the low temperature. If you need durability motor, then choose high HC motor segment magnets.
4. Magnetic energy product (BH) max.: the higher (BH) max. , the better working coefficient of permanent segment magnets in the motor actual operation.
5. Magnetic flux: the bigger the better; it will greatly improve the work efficiency of the motor.
6. The rectangle degree of the demagnetization curve: the higher rectangle factor , the smaller the dynamic losses in the motor.
7. The higher resistivity, the smaller the eddy current losses.

3. How to choose motor segment material?

For traditional AC motor, ferrite and AlNiCo segment magnets are most applied. With the higher request on motor power, more and more motor manufacturers use ndfeb and smco magnet which have super high magnetic energy product. However, they are more expensive because neodymium magnet and samarium cobalt magnet segments belong to rare earth magnet. Please click here to get more analysis of different magnet material.

4. Permanent Magnet: the core of PM motor

In order to guarantee the steadily electrical performance and long-term safe and reliable operation of electric vehicles, it requires the magnetic property of permanent magnet material remains stable. Considering magnetic performance influenced by work environment, temperature and time, the reliability of permanent motor magnets can be divided into thermal stability, time stability, chemical stability and magnetic stability.

1. Temperature stability can be shown by Curie temperature and the maximum operating temperature. As the temperature rises, the magnetic properties gradually reduce. When raises to a certain temperature, the magnetization disappear. This certain temperature is the Curie temperature of the permanent magnet materials, also known as the Curie point. The deficiency of NdFeB permanent magnet is relatively low Curie temperature, but higher temperature coefficient.Thus neodymium magnet will lost much magnetic force if work under high temperature. Due to the high temperature coefficient of NdFeB permanent magnet, the magnetic properties is poor. To this end, it must pay more attention to Max. working temp.of sintered nedfeb magnet when you select an magnet grade. The test method of magnet temperature stability is aging test
2. Time stability is putting the permanent magnet at a certain temperature for a long time, observing the change of its magnetic properties over time. These NdFeB permanent magnets added Co + Dy + Nb will obtain better time stability.
3. Chemical stability refers to the anti-oxidation and corrosion-resistant of permanent magnet material. Compared with the traditional ferrite or samarium cobalt (Smco) or alnico magnets, the chemical stability of sintered NdFeB magnet is the worst. Currently, the primarily solution is adding some alloy elements such as Co, Ni, Al and Cr, etc., while in the sintering process, increasing the density and reducing the porosity of magnetic material.Another approach is make certain magnet surface treatment such as electroplating. This can obtain a practical corrosion resistance for magnet.
4. Magnetic stability is based on magnetic material, and also affected by temperature, time, external magnetic field, chemical corrosion, radiation, mechanical vibration or shock and other factors.

5. How to join neodymium magnet arcs, which are diameter magnetized, to create a cylindrical ring that is radially magnetized?

The general approach is to make a sleeve or frame to put arc magnets in that will keep them in order and don’t jump around. The sleeve here has to be made of something sturdy and nonmagnetic, such as aluminum, copper or Q235 low carbon steel. Due to strong repelling force, it’s better to operate by those experienced workers. If you are the first time to assemble segment magnets, just be careful. Halbach array magnets also utilize frame or other tools to overcome the strong magnetic repulsive force between the same pole sides of two magnets and keep them fixing together.

6. Motor Magnet Customized Service

According to special requirement of different motors or generators, there is few standard segment rotor magnets available on the market for customers to choose. Every motor manufacturer will design different product based on their technology, market direction, therefore segment magnets of motor rotor need to be customized. China Magnets Source Material Ltd a professional magnets manufacturer for many years and specialized in motor NdFeB magnet. When you ask for a quote, please provide detailed information as follow:

1. Material: Sintered Neodymium Iron Boron Magnets or bonded ndfeb magnet or samarium cobalt or alnico magnet or ferrite magnet
2. Grade: please click here and select from our table
3. Coating: please click here and select from our table
4. Size: drawing is needed for segment magnet
5. Magnetize or Not:
6. Magnetized Direction: please show on drawing
7. Quantity: we don't have MOQ, but price will be cheaper if you order more at a time

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

Insert Moudling / Over Moulding / Injection Molded (Plastic) Sintered Neodymium Magnets

Is it possible to insert mould a sintered neodymium magnet inside a plastic injection moulded part?

If you’re looking for an assembly of round magnets into an ABS housing, then you’ll LOVE this article.

What technique do you use to stick the magnet on the ABS part?

One solution is using 3M double sided tape, Loctite glue s or AB glue. But this is not a fixed component. Even you try many different glues and sometimes it will fail.



If you need permanent fixation, the other good solution is INSERT MOUDING. The sintered NdFeB magnet manufacturerd by injection molded technique is also called plastic coated magnet. It is colorful, weatherproof and more durable than uncoated magnet or normal coated NiCuNi, Zn magnets, avoiding gluing the magnet as a secondary process. You may have a tooling charge (if a existing tool cannot be used or modified) and depending on the magnetic assembly, a magnetising fixture may be required as well.



Why overmolding would work with N42 or N45 grade magnet as I know the injection temperature of ABS is over 200°C ?

It is true that all magnets are affected by heat. And the maximum working temperature of sintered neodymium from N to AH series is among 80℃-220 ℃ which is lower than injection molding. That’s why, generally, when it comes to injection molded magnet, you’ve heard enough about bonded ndfeb magnet, samarium cobalt magnet and ferrite magnet for one lifetime.

Because of 250 degree celsius high temperature of the plastic mold, only these ferrite, smco and bonded ndfeb magnets which can work under higher temperature environment are suitable for injection molding manufacture. Why we insist on using sintered ndfeb magnet here even it’s hard to make: super power magnetic force is the most important factor and no other magnet in the world can take the place of sintered ndfeb magnet.



Okay, how N42 Sintered NdFeB magnet work here? 

When overmold process is fast, like about 10-40 seconds. This short time has few influence on magnetic force. Because the outside of the magnet expose all the heat but the inner volume may not get so hot. Meanwhile, you may have to choose a stronger magnet or higher working temp. Magnet than your original design to avoid any demagnetization during overmolding process.

All options you can choose for permanent SINTERED NDFEB magnet overmolding:

1. Overmold 80 ℃ sintered neodymium magnet (unmagnetized), and then magnetize the full component (depends on the size of assembly).
2. Overmold a standard 80℃ sintered NdFeB magnet (magnetized), and then fully re-charged the assembly (depends on the size of assembly).
3. Overmold a higher Hci NdFeB magnet (magnetised), but it cost more.
4. Put sintered NdFeB in plastic housing, add plastic cap, and then ultrasonic weld seal.



China Magnets Source Material Limited is a professional plastic magnet manufacturer for many years. We also manufacture magnetic assembly according to your special requirements.

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

Rare Earth Neodymium Magnet in a magnetic levitation display

Custom Permanent Magnet Manufacturer

China Magnets Source Material Ltd manufactures #permanent_magnets (instagram) in many shapes, sizes, and grades of neodymium, samarium cobalt, alnico and ferrite materials. The best way to contact us is by e-mail with a detailed description of your magnets. There is a guide to help you understand what we need for a quote.



Why Buy Magnet From China Magnets Source Material Ltd?

• Quick Response  All emails will be replied within 48 hours. #ChinaMagnetsSML (instagram) is a customer-focused rare earth magnet supplier / manufacturer. Our working time is 8:30 – 12:00, 13:00 – 17:30 (Monday - Friday) which fully consider the rest time of our staffs. We hope our staffs come back to work more motivated and energetic. This also guarantees fast reply to our customers.
• Manufacturing Capacity  For industry application or daily life items, #ChinaMagnetsSML (instagram) can produce custom magnets from neodymium material to smco, alnico and ferrite materials; from sample & prototype to large volumes, from simple to complicated shapes, from single magnet to magnetic components.
• Stable Resource  Reliable procurement channel for raw materials and strict material testing process ensure product performance.
• Certificate  ISO9001:2008, ISO/TS 16949:2009, SGS, Rohs, REACH

      

• MOQ  Please note that there is no minimum order quantity required no matter for normal magnets or for custom magnets.
• Just in time delivery Normal lead time for normal magnets is 3-4 Weeks; normal lead time for custom magnets is 4-5 Weeks.
• Shipping Agent  Our sea & air & EXPRESS agents are senior in their field that have long-term business relationship with us, offering the cheapest transport cost and fast transit time.
• Design Suggestion  #ChinaMagnetsSML (instagram) will be happy to provide magnet or magnetic assembly design & engineering assistance, and rapid prototype manufacture.
• Customers  Our extensive experience in manufacturing neodymium magnet, samarium cobalt, alnico magnet and ferrite magnet help us to win the trust of customers all over the world. Some of our representative customers are listed below.