Motor stator assemblies need magnets that hold their shape under continuous heat and fit the bore with almost no clearance. HIMAGNET's 45SH arc segment magnets are built for exactly that - radially magnetized, precision cut to ±0.05mm, and rated for stable operation above 150°C. If your DC motor, step motor, or servo stator is running hot and your current supplier's tolerances keep drifting, this is the part worth testing.
The 45SH designation refers to the SH grade family - a high-coercivity variant of sintered NdFeB developed specifically for elevated operating temperatures. Where standard N-grade magnets start losing meaningful flux above roughly 80°C, the SH series holds its magnetic output much further into the thermal range, which matters most in motors that run continuously under load rather than in short bursts.
Why Radial Magnetization Matters Here
Arc segment magnets for motor stators are magnetized radially - meaning the field runs outward through the curved face rather than through the flat ends. This orientation is what produces the even, predictable field distribution that motor designers rely on for consistent torque. Getting this wrong (or working with a supplier who can't confirm magnetization direction) leads to uneven cogging and inconsistent motor performance across a production batch.
Every arc segment we cut carries a ±0.05mm tolerance on the finished dimensions. In practical terms, that's the difference between a segment that seats cleanly against the stator bore and one that needs shimming or rework on the assembly line. For OEM buyers running automated stator winding lines, that tolerance consistency across a full production batch is often the deciding factor over raw magnetic strength.
Coating and Surface Protection
Standard finish is Ni-Cu-Ni (nickel-copper-nickel) triple-layer plating, which handles normal indoor motor housing environments without issue. For motors operating in humid, marine, or chemically exposed conditions, we can switch to epoxy or zinc coating instead - both are available at the same cutting tolerance and lead time impact is minimal since coating is applied after machining.
Where These Are Used
The primary application is DC and step motor stators, but we've also supplied these arc segments for servo motor assemblies, small generators, and elevator traction machine rotors where the SH grade's high-temperature stability is specifically required. If your application runs a duty cycle that generates sustained heat inside the housing, this is where SH grade earns its cost premium over standard N-series material.
Customization and Cutting Service
Every stator is a little different, so we don't stock a fixed catalog of arc dimensions. Instead, send us your inner radius, outer radius, arc length, and pole arc coefficient (or a CAD drawing if you have one), and we'll cut to match. Grade selection runs from 35SH up through 48SH for higher-temperature requirements, and we can also process UH and EH series material for applications running above the SH range.
There is no fixed minimum order quantity. We handle both prototype quantities for motor design validation and full production runs for OEM supply contracts.
Common Questions
What information do you need to quote a custom arc magnet?
Inner radius, outer radius, arc length, pole arc coefficient, grade (e.g. 42SH or 45SH), and coating preference. A CAD drawing or existing sample speeds up the quote significantly, but we can also work from written dimensions.
What's the actual difference between SH grade and standard N grade?
SH grade has higher intrinsic coercivity, which means it resists demagnetization at elevated temperatures. Standard N-series magnets are rated to roughly 80°C; SH grade maintains stable output well above 150°C. If your motor housing runs hot under continuous load, SH is the safer choice even though the material cost is higher.
Can you match the exact arc angle of our existing supplier's part?
Yes - send us a sample or the original drawing and we'll match the pole arc coefficient and dimensions. This is a common request when qualifying a second source for an existing motor design.
To request a quote, send us your stator bore dimensions, grade requirement, and quantity. We typically respond within one business day with pricing and lead time.
HIMAGNET - Sintered NdFeB Magnet Manufacturer | ISO9001 Certified | Fujian, China
Hot Tags: 45sh neodymium arc magnet for dc & step motors, manufacturers, suppliers, factory, customized
