Ring Magnets for Motors & Generators
What Are Motor Ring Magnets?
Motor ring magnets are hollow cylindrical permanent magnets serving as rotor magnetic sources for PM motors. Compared with spliced arc magnets, integrated ring magnets form smoother, more continuous magnetic fields, drastically lowering cogging torque and torque ripple for steadier motor operation.
In BLDC and PMSM motors, ring magnets are fitted onto rotor cores and rotate with shafts, generating torque via magnetic interaction with stator windings. Key parameters including pole count, pole arc coefficient and magnetization mode directly determine motor efficiency, noise and vibration performance.
At Fullzen Technology, we manufacture both sintered and bonded neodymium ring magnets. Our magnetization solutions cover simple 2-pole radial designs up to complex 128-pole multipole and Halbach array magnetization, fully matching diverse motor design requirements.
Typical Applications
| Item | Specification Range |
|---|---|
| Magnet Grades | N35 ~ N52, M/H/SH/UH/EH/AH temperature series |
| Outer Diameter (OD) | φ10mm ~ φ300mm, fully customizable |
| Inner Diameter (ID) | φ5mm ~ φ280mm, custom sizes available |
| Axial Length (L) | 2mm ~ 150mm, laminated stacking supported |
| Dimensional Tolerance | OD/ID: ±0.02mm ~ ±0.1mm; Length: ±0.05mm |
| Magnetization Types | Radial, axial, 2–128 poles multipole, skew pole, Halbach array |
| Remanence (Br) | 11.7 ~ 14.8 kGs |
| Intrinsic Coercivity (Hcj) | 12 ~ 38 kOe |
| Max Operating Temp | 80℃ ~ 220℃, subject to magnet grade |
| Surface Coatings | Ni-Cu-Ni, zinc, epoxy, parylene, aluminum chromate |
| Air Gap Flux Density | 3000 ~ 8000 Gs, based on magnetic circuit design |
| Harmonic Distortion Rate | ≤1.5% for precision grade |
| Certifications | ISO 9001, IATF 16949, RoHS, REACH |
Key Advantages
Our motor-grade sintered ring magnets adopt advanced powder metallurgy and sintering techniques, bringing prominent competitive strengths for motor manufacturers:
1、High Energy Density
N52 grade reaches maximum magnetic energy product of 53 MGOe. Identical volume enables over 40% higher motor output power, facilitating equipment miniaturization and lightweight design.
2、Precision Custom Magnetization
With self-developed magnetizing fixtures, we realize 2–128 pole multipole and skew magnetization to minimize cogging torque, enabling smoother rotation and lower noise.
3、Low Eddy Current Loss
Segmented and laminated structures are optional, slashing eddy loss by 30–60% to control temperature rise and extend motor service life.
4、Ultra-Tight Dimensional Precision
OD & ID tolerance as tight as ±0.02mm with coaxiality ≤0.03mm, ensuring uniform air gap and stable batch magnetic performance consistency.
5、Wide Temperature Adaptability
Covers normal ambient temperature up to 220℃ high-temperature range. High-temperature UH/EH/AH grades fit harsh working conditions for automotive and wind power equipment.
6、Automotive-Quality Reliability
Certified to IATF 16949, we provide complete PPAP documents with full production traceability to meet strict reliability standards of automotive electronics.
Common Applications
Fullzen ring magnets are widely deployed in high-performance motors and generators across multiple industries:
Sintered vs Bonded vs Ferrite in Motors
| Comparison Item | Sintered NdFeB | Bonded NdFeB | Ferrite |
|---|---|---|---|
| Max Magnetic Energy Product | 53 MGOe | 12 MGOe | 4.5 MGOe |
| Air Gap Flux Density | 6000–8000 Gs | 2500–4000 Gs | 1500–2500 Gs |
| Power Density | Extremely High | Medium | Low |
| Dimensional Precision | ±0.02mm | ±0.01mm | ±0.1mm |
| Max Working Temp | 80–220℃ | ≤150℃ | ≤250℃ |
| Cost | High | Medium | Low |
| Suitable Scenarios | High-performance motors, EVs | Micro precision motors, complex irregular shapes | General low-cost motors |
Fullzen Capabilities
With 15 years of R&D and manufacturing experience in neodymium magnets, Fullzen produces over 2,000 tons of motor-grade magnetic rings annually, covering the full industrial chain from rare earth raw material processing to finished magnetization.
R&D & Design Capacity：
Finite element magnetic circuit simulation to optimize air gap flux density and sinusoidal waveform
Custom magnet grade and magnetization scheme recommendation aligned with your motor performance targets
Fast sample development with 15–20 days turnaround for verification prototypes
Joint motor performance testing and iterative design optimization with clients
Production & Machining Capacity：
Near-net-shape sintering technology for high material utilization and consistent performance
Precision internal & external cylindrical grinding, surface grinding for ±0.02mm tight tolerance
Wire-cut segmented magnetic rings for low eddy current loss designs
Compression & injection molding for bonded ring magnets, suitable for mass complex-shape production
Magnetization & Testing Capacity：
Self-designed magnetizing fixtures supporting radial, axial, multipole and Halbach magnetization
3D magnetic field mapping to verify magnetization waveform compliance with design standards
100% dimensional and magnetic flux inspection on all finished products
Reliability validation including high-temperature aging and salt spray testing
Custom Solutions
Every motor model carries unique design requirements, and Fullzen delivers full-spectrum customized magnetic ring solutions:
Grade Customization: Full series N35~N52, M/H/SH/UH/EH/AH high-temperature grades
Size Customization: OD 10–300mm, ID 5–280mm, axial length 2–150mm
Magnetization Customization: Radial, axial, 2–128 poles multipole, skew pole, Halbach array
Structural Customization: Monolithic, segmented, laminated stacks for various loss control demands
Coating Customization: Ni-Cu-Ni, epoxy, parylene, zinc, aluminum chromate anti-corrosion layers
Assembly Customization: Magnet bonding, rotor dynamic balancing, overmolding and other value-added services
Sample Program
We offer flexible sample services to match different stages of motor development:
| Sample Type | Lead Time | Cost Policy |
|---|---|---|
| Standard Stock Sizes | 3–5 working days | Free within 5 pcs, customer bears shipping cost |
| Semi-Custom (Stock blank + custom magnetization) | 7–10 working days | Magnetizing fixture fee charged, fully refundable upon mass order placement |
| Fully Custom Sintered Ring Magnets | 15–25 working days | Mould fee charged, refundable for bulk orders |
| Fully Custom Bonded Ring Magnets | 20–30 working days | Mould fee applicable, negotiable based on order volume |
Quality Assurance
Stable magnet quality lays the foundation for reliable motor operation, and Fullzen maintains a full-process quality control system:
Dual certification of ISO 9001 and IATF 16949 automotive quality management systems
100% incoming raw material inspection to qualify rare earth composition and impurity limits
SPC statistical process control during sintering to restrict magnetic performance fluctuation within 3%
Complete dimensional and magnetic flux testing for all finished products
Material certificates and inspection reports provided per batch
RoHS & REACH compliance, conflict mineral statements available on request
Tier 3 PPAP documents accessible for automotive-grade customers
Why Choose Fullzen for Motor & Generator Ring Magnets?
Fullzen Technology has supplied magnetic ring solutions to more than 500 motor manufacturers worldwide. Here is why our partners trust us long-term:
Frequently Asked Questions
We sorted out 8 core concerns raised during motor ring magnet procurement, covering grade selection, customization, performance and lead times to speed up your decision-making. Contact our engineering team for deeper technical consultation or magnetic circuit design support.
Grade selection depends primarily on your motor’s maximum operating temperature and target air gap flux density. Standard N grades offer cost efficiency under 80℃; M/H series fit 100–150℃ working environments; SH/UH grades apply to 150–180℃ motors; EH/AH high-temperature grades work above 180℃. Always reserve temperature margin to avoid irreversible demagnetization. Our engineers can recommend exact grades based on your motor parameters.
Sample stage: 15–25 days for sintered rings, 20–30 days for bonded rings. Mass production: 45–60 days after sample confirmation. Standard stock items ship within 3–5 days. We provide VMI consignment inventory for long-term partners to eliminate waiting time.
Yes. Fullzen independently designs and manufactures magnetizing fixtures supporting radial, axial, 2–128 pole multipole, skew pole and Halbach array magnetization. We optimize pole arc coefficients and inter-pole transition parameters per your motor performance goals, supply magnetization waveform simulation reports and deliver physical prototypes for real performance verification.
Three mainstream technical solutions: segmented design cutting loss by 30–60% with insulation between segments; laminated thin magnet sheet stacking; high-resistivity bonded NdFeB materials. The optimal solution will be recommended after evaluating your motor operating frequency, power density and budget.
Standard grade: OD/ID ±0.05mm, length ±0.05mm, coaxiality ≤0.05mm. Precision grade: OD/ID ±0.02mm, length ±0.03mm, coaxiality ≤0.03mm. Higher precision is achievable via enhanced grinding processes, subject to size range and process feasibility assessment.
Under standard operating conditions (temperature below max rating, no irreversible demagnetization, intact anti-corrosion coating), sintered neodymium ring magnets maintain stable performance for 15–20 years. Thermal aging is the main cause of performance decay; annual attenuation rate stays below 0.1% under 100℃. Fullzen provides high-temperature aging test data for lifespan evaluation.
Yes. We provide value-added services including magnet bonding, rotor assembly and dynamic balancing testing. High-temperature structural adhesive bonds magnets onto shafts, with dynamic balancing and magnetic testing finished before delivery, enabling direct motor assembly upon receipt and simplifying your production workflow while guaranteeing mounting precision.
Strict minimum quantity is not required for sample orders, ranging from several pieces to dozens. For mass production, MOQ is normally 500–1000 pieces for sintered rings; bonded ring MOQ is usually 2000 pieces due to higher mould costs. MOQ can be adjusted flexibly according to magnet size, process complexity and cooperation history.
Related Ring Magnet Products
Browse our full range of neodymium ring magnet solutions for various motor and generator applications:
Neodymium Ring Magnets – Complete selection guide covering all grades, sizes and magnetization types
Radially Magnetized Ring Magnets – Inner-outer pole radial rings for motors and sensors
N42 Neodymium Ring Magnets – Highest mass-produced energy grade, top choice for miniaturized motor designs
Large Neodymium Ring Magnets – Custom oversized rings above 200mm OD for wind power generators and MRI equipment
Request Your Free Quote Toda
Send over your motor design drawings or performance parameters, and Fullzen’s engineering team will deliver customized material selection, quotation and lead time solutions within 24 hours.
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