Motor Stator · Permanent Magnet Stator
GX Magnet supplies permanent-magnet stator assemblies manufactured to customer drawings, incorporating ferrite or sintered NdFeB arc magnets, these assemblies are integrated into a customer-specified steel yoke or motor housing. This page covers the magnetic stator assembly only; copper windings, busbars and winding temperature sensors are excluded.
Project screening
To evaluate a permanent-magnet stator, GX needs the stator construction, magnetic-circuit requirements, mechanical interfaces and operating conditions—not only a product name or sample photo.
Engineered for precision and durability, our advanced magnet assemblies meet the rigorous demands of global industrial applications.
Steel housing inner wall is fitted with two arc magnet segments placed opposite each other, one N pole and one S pole, 180° apart, forming one pair of magnetic poles. A wound armature is installed at the center.This is the simplest permanent magnet stator structure, with the fewest components and a direct magnetic circuit. The magnets can be made from sintered ferrite, NdFeB or injection-molded magnetic material, and supplied as a stator assembly with the steel housing and bearing structure.
Four arc magnet segments are evenly spaced at 90° intervals along the inner wall of the housing and arranged in an alternating N–S–N–S pattern to form two pole pairs. This configuration provides a more uniform air-gap magnetic field and doubles the number of electrical cycles per mechanical revolution compared with a two-pole design. It is a widely used, cost-effective configuration for small and special-purpose motors, including automotive auxiliary motors and household-appliance pump motors.
Six or more magnet segments can be closely assembled along the inner wall. Alternatively, a multipole ring magnet or Halbach flux-concentrating array can be used. Increasing the pole count and optimizing each segment’s magnetization direction concentrates the field toward the air gap, increasing flux density. This configuration is intended for high torque density, smooth operation, and low-speed direct-drive applications.
Ferrite or NdFeB arc magnets are assembled inside the housing according to the specified pole count, then bonded and cured. The delivered product is a completed stator assembly consisting of the magnets and steel housing.
This permanent-magnet stator uses sintered anisotropic hard-ferrite arc segments made from iron oxide with strontium or barium compounds. The black, ceramic-like magnets are installed in a steel housing. Their magnetic performance is moderate, with a maximum energy product of approximately 1–4.5 MGOe, but they offer stable material cost, inherent corrosion resistance, and suitability for high-volume production. This is a mainstream, well-established material choice for PMDC motors.
This permanent-magnet stator uses sintered NdFeB magnets installed in a steel housing. With a maximum energy product of 30–55 MGOe, its air-gap flux density can reach 0.6–1.0 T, depending on the design. It is intended for space-constrained projects requiring higher magnetic flux density and torque density, as well as further miniaturization. Because NdFeB is sensitive to temperature and corrosion, every stator in this series is customized after evaluating the customer’s drawings and operating conditions.
Up to 80% of a stator’s performance is determined during magnet forming and sintering. GX maintains end-to-end process control—from powder formulation, magnetic-field orientation and sintering profiles to GBD, multipole magnetization, precision grinding and coating.
GX Magnet supports three material routes for stator applications: sintered ferrite, sintered NdFeB, and bonded or injection-molded magnets.
The degree of orientation in an anisotropic magnet determines how consistently its easy-magnetization axis is aligned. This provides the basis for increasing Br and (BH)max while using the same material composition and magnet volume.
GX Magnet supports sintered NdFeB grades from the N series through the AH series, with three grain boundary diffusion (GBD) routes available: spray coating, screen printing and PVD.
Material consistency directly affects flux variation between the magnetic poles within the same stator and between different production batches.
Fewer process interfaces, tighter control of the air gap and concentricity, and improved batch-to-batch consistency for permanent-magnet stators.
Depending on the stator design and operating conditions, GX can select the appropriate magnet-retention method, including structural adhesive bonding, mechanical retention, insert overmolding and stainless-steel sleeves. Magnet supply, yoke and housing machining, automated magnet placement, CCD vision alignment, servo pressing, in-line curing and automated magnetization are integrated into one manufacturing and quality-control chain.
By controlling magnet dimensions, housing datums, adhesive-layer thickness and assembly position within one system, GX enables closed-loop control of the air-gap dimensional stack-up. Concentricity at critical mating features can be controlled to 0.01 mm according to project requirements.
Magnetic performance, assembly dimensions and final magnetization results can all be verified together. This reduces datum shifts, quality handoffs and delivery variation caused by multiple subcontracting stages, helping ensure air-gap uniformity, consistent flux and repeatable quality across permanent-magnet stator batches.
Product and supply scope
In the supply scope of this page, a permanent magnet stator is the stationary magnetic-field assembly used in PMDC and related motor structures. Ferrite arc magnets are positioned and retained inside a steel yoke or motor housing around the rotor working gap.
GX evaluates the magnet geometry, pole layout, steel interface, retention method, air-gap relationship and inspection plan from the customer drawing. Copper winding, a stator bus bar and a winding temperature sensor are outside this page’s stated supply scope.
Drawing variables
The magnet specification, pole layout, housing and air-gap interfaces, and retention method should be reviewed together because each affects magnetic performance, assembly accuracy and production feasibility.
| Parameter | Specification / Review Basis |
|---|---|
| Stator Structure | Ferrite arc magnet segments assembled inside a drawing-defined steel yoke or motor housing |
| Magnet Material | Hard ferrite / ceramic ferrite according to the approved project specification |
| Pole Configuration | Two-pole, four-pole or project-defined multi-segment arrangement |
| Magnetization | Direction, pole sequence and installed orientation confirmed from the pole map and drawing |
| Key Interfaces | Magnet arc, housing inner diameter, rotor diameter, working air gap, datums and retention method |
| Operating Conditions | Temperature, moisture, chemicals, vibration and validation cycle reviewed by application |
| Customization Basis | 2D/3D drawings, mating-rotor information, sample quantity and annual demand |
| Acceptance Basis | Approved drawing, sample and agreed dimensional, magnetic and assembly inspection method |
Project route
GX connects ferrite magnet selection, housing interface, assembly planning, magnetization verification and recurring inspection to one approved project route.
Motor type, drawing, rotor interface, environment, tolerances and demand are checked together.
Pole layout, ferrite arc geometry, steel yoke and retention concept are compared with the application.
Datums, critical dimensions, assembly access and measurement points are confirmed.
Confirmed ferrite segments and steel components are prepared under drawing control.
Pole position, dimensions, retention and magnetic result are checked before approval.
Approved drawings, samples and inspection criteria govern recurring batches.
Verification
The control plan follows the approved drawing and the project’s agreed dimensional, magnetic, mechanical and appearance requirements.
| Inspection item | Control approach | Why the buyer needs it |
|---|---|---|
| Housing and magnet dimensions | Critical dimensions and datums checked with agreed gauges or measurement methods | Controls fit and working-gap consistency |
| Concentricity / runout | Rotor-related datum and inner working surface evaluated where specified | Supports stable air gap and motor operation |
| Magnetic result | Agreed property, pole pattern or functional check under defined conditions | Connects the stator to the approved motor design |
| Polarity and position | Direction, pole sequence and circumferential position verified to drawing | Prevents incorrect assembly or rotation behavior |
| Retention / appearance | Joint, edge, contamination and appearance criteria evaluated to the agreed standard | Reduces assembly interference and acceptance disputes |
Application fit
Application fit depends on pole layout, housing interface, air gap, operating environment and the required production repeatability.
Two-pole structures are reviewed with rotor diameter, working gap, torque target and housing interface.
Pole position, moisture exposure, retention and the mating rotor are evaluated together.
Assembly repeatability, noise-related constraints and dimensional acceptance follow the motor drawing.
Special housings, pole layouts and interfaces are quoted only after drawing and project review.
Quality-system support
Drawing revision, sample approval and project-defined inspection can be supported through the applicable manufacturing quality system. The relevant ISO or IATF certificate holder, site and scope are confirmed for each program.
Magnet geometry, housing datums, pole layout, retention and appearance criteria follow the approved drawing revision.
Prototype dimensions and agreed magnetic, fit or functional checks are recorded before recurring production.
Inspection scope and sampling expectations are aligned before quotation and release.
Available certificates, inspection records and magnetic test data are provided according to the responsible site, approved drawing and agreed acceptance criteria.
Buyer communication
Industry events provide a practical setting to compare ferrite arc geometries, housing concepts and pole-layout requirements with GX’s engineering and sourcing team.
Bring the stator drawing, mating-rotor information or a magnetic-function question. The discussion can identify the supply boundary, interface risks and RFQ information needed before formal engineering review.
Compare pole layouts, housings and stator forms before choosing the quotation route.
Review air gap, interfaces, environment and validation expectations.
Plan drawing review, sample approval, inspection evidence and recurring communication.
GX Magnet
GX coordinates ferrite-magnet, steel-housing and assembly resources for drawing-controlled fixed-stator programs across motor and actuator applications.
Ferrite magnet material, pole layout, steel interface and retention are reviewed against the application.
Tooling, interfaces, samples and inspection criteria are controlled from approved revisions.
Engineering and sourcing teams receive a clear RFQ input list and project-specific supply boundary.
FAQ
These answers focus on pole layout, housing integration and the boundary of a ferrite fixed-field stator assembly.
Both process routes are possible. Pre-magnetized segments can be inspected individually, but their magnetic attraction makes positioning, bonding and contamination control more difficult. Post-assembly magnetization simplifies magnet placement and creates the final pole pattern after the magnets are fixed. However, it requires a magnetizing fixture compatible with the housing geometry, magnet material and pole count. The appropriate route should be selected during the manufacturability review.
Consistency begins with controlling magnet material properties, dimensions, orientation and magnetization. During assembly, magnet position, pole pitch, bond-line thickness, radial location and housing concentricity must also remain stable. The completed stator can then be checked by measuring flux per pole or mapping the air-gap flux-density waveform. The inspection fixture, probe position, air gap and test temperature should remain fixed so results can be compared between poles and production batches.
Yes. Two-pole, four-pole and other segment arrangements can be evaluated from the pole map, magnet drawing, steel housing, mating rotor and acceptance method.
Yes. In many permanent-magnet stators, the steel housing serves both as the structural enclosure and as the magnetic flux return path. Its material permeability, wall thickness, openings and joints can affect magnetic reluctance, leakage flux and local saturation. The housing ID and concentricity also influence the working air gap. For this reason, the housing should be included in magnetic-circuit evaluation rather than treated as an independent mechanical component.
Testing normally begins with visual and dimensional inspection, including the housing ID, magnet position, air-gap diameter, concentricity and runout. Magnetic inspection verifies the pole count, N/S sequence, installed polarity, flux per pole and air-gap flux-density distribution. Depending on the application, validation may also include magnet-retention tests, back-EMF or torque testing with the mating rotor, thermal cycling, vibration and corrosion testing. Magnetic acceptance limits should always specify the fixture, probe position, air gap and test temperature.
Ferrite arc magnets provide stable material cost, inherent corrosion resistance and good suitability for high-volume motor production, but their magnetic energy density is lower. Sintered NdFeB magnets can produce higher air-gap flux density and support smaller, higher-torque-density motor designs. However, the NdFeB grade, coating and magnetic operating point must be selected for the expected temperature and corrosion environment. Material selection should therefore be based on the complete magnetic circuit rather than magnet strength alone.
Pole count influences pole pitch, electrical frequency, torque characteristics and magnetic-field distribution. Increasing the number of poles can support smoother low-speed operation, but it also increases sensitivity to magnet position, pole-to-pole variation and magnetic leakage. A smaller air gap generally improves magnetic coupling and usable air-gap flux density, while requiring tighter control of housing concentricity, rotor runout and assembly clearance. Both parameters should be evaluated with the mating rotor and drive conditions.
Common retention methods include structural adhesive bonding, mechanical clips or locating features, injection encapsulation and nonmagnetic retaining sleeves. The appropriate method depends on the magnet material, housing geometry, operating temperature, vibration, shock, corrosion exposure and required service life. For bonded assemblies, the drawing and process specification should define surface preparation, bond-line thickness, adhesive coverage and curing conditions. Retention should then be verified using an agreed mechanical test and acceptance criterion.
As temperature rises, magnet remanence changes and intrinsic coercivity may decrease. If the magnetic operating point crosses the knee of the demagnetization curve, irreversible flux loss can occur. The risk depends on the magnet material and grade, magnet geometry, air gap, housing magnetic circuit, opposing armature field, duty cycle and peak temperature. A maximum operating-temperature value should therefore not be selected from the magnet grade alone; the complete stator and motor operating conditions must be reviewed.
Magnet grade is only one input. Finished-stator performance is also affected by magnet dimensions, orientation, magnetization level, pole position, housing permeability, bond-line thickness, air-gap geometry, concentricity and the mating rotor. Measurement fixtures and probe positions can create additional differences. For production control, the completed stator should be evaluated using drawing-defined criteria such as pole sequence, flux per pole, air-gap flux-density waveform or motor-level back-EMF—not only the material grade.
Request for quotation
Include the motor type, 2D/3D drawings, pole layout, rotor and housing interfaces, operating environment, sample quantity and annual demand.
