Run the arc magnet magnetic field diagram checker first to map your arc-magnet geometry and field-direction assumptions into a usable diagram path. Then use the report layer to verify method boundaries, evidence quality, and RFQ-ready risk controls on the same URL.
Diagram preview is explanatory, not a final simulation mesh. Always carry boundary notes into next-stage analysis.
| Observed pattern | What it implies | Page decision |
|---|---|---|
| Top results mix supplier pages, generic diagrams, and forum-style sketches with inconsistent assumptions. | Users need an executable checker before reading a long explanation. | Put tool input/output above the fold and force explicit boundary notes. |
| Most pages do not distinguish quick illustration diagrams from FEA-ready magnetic models. | Teams often copy a picture that is not valid for simulation handoff. | Add diagram-goal selection and output-specific next actions. |
| Alias confusion between radial, circumference, and segmented-parallel magnetization remains common. | Wrong terminology can create wrong RFQ notes and wrong field assumptions. | Show mode comparison table and explicit suitable/not-suitable audience split. |
| Gap found in prior version | Decision impact | Stage1b repair action | Evidence map | Status |
|---|---|---|---|---|
| Thresholds were easy to misread as universal pass/fail standards. | Wrong gate criteria can propagate into RFQ and simulation handoff. | Split evidence-backed findings from in-page screening heuristics and add explicit caveat labels. | S2, S4, S5, S8 | Closed |
| Concept boundaries between material standards, FEA model scope, and diagram scope were mixed. | Teams may treat IEC material compliance as assembly-level field validity. | Add concept-boundary matrix with applicability and non-applicability clauses. | S3, S6, S7 | Closed |
| Segment and arc-span discussion lacked quantified public references. | Segment-count and arc-angle decisions looked opinion-based. | Add quantified deltas from Sensors 2014 and slot/pole dependency constraints from IEEE 2000. | S4, S5 | Closed |
| High-speed risk threshold did not distinguish conservative trigger vs hard standard. | Users could over-reject designs above a single speed cutoff. | Anchor speed context to high-speed PM review and tag 65 m/s as conservative screening trigger only. | S8 | Closed |
| Supply-chain risk section had weak data-time coupling. | Commercial risk guidance could age quickly without date markers. | Add USGS 2026 and IEA 2025 data points with explicit year context and update note. | S9, S10 | Closed |
| New fact | Why it changes decisions | Time marker | Source |
|---|---|---|---|
| FEMM radial note warns that large arc coverage can create significant difference between constant (diametral) and radial magnetization direction (example shown at 80 deg arc). | Supports stricter arc-span caution and explicit mode wording before simulation handoff. | Page last modified: 2026-05-03 | S2 |
| Sensors 2014 reports normalized force for segmented parallel magnetization: F~2 = 0.64, F~8 simulation = 0.979, F~8 measured = 0.961, and 12 segments approach about 1% loss. | Provides evidence for using >=8 segments as a stronger approximation route than low-segment layouts. | Published: 2014-07-21 | S4 |
| IEEE Transactions (2000) shows optimal pole-arc to pole-pitch ratio depends on slot/pole combination and fringing correction factor (typically 0.01-0.03). | Confirms there is no single universal coverage ratio threshold across all PM topologies. | Published: 2000-12 | S5 |
| High-speed PM review defines typical high-speed operation above 10,000 rpm and above 50 m/s circumferential speed, with some designs reaching around 200 m/s and above. | Justifies using 65 m/s as a conservative risk trigger, not as a universal rejection rule. | Published: 2022-07-07 | S8 |
| USGS 2026 rare-earth sheet reports U.S. 2025 import reliance at 67% for compounds/metals and 71% import-source share from China (2021-24). | Adds concrete procurement exposure context when diagram choices enter RFQ and supplier decisions. | USGS issue date: 2026-02 | S9 |
| IEA 2025 executive summary reports top-3 refining share rising from about 82% (2020) to 86% (2024), and widening export-control scope after 2023. | Supports adding concentration-risk and disruption scenarios to decision tradeoff guidance. | Report year: 2025 (accessed 2026-05) | S10 |
| Step | Logic | Output |
|---|---|---|
| Normalize geometry | Compute mean radius, arc length, pole pitch, and coverage ratio from OD/ID/arc/pole pairs. | Coverage metrics for diagram plausibility checks. |
| Score direction fit | Apply mode-specific base score and adjust by use-case and diagram goal. | Fit score that maps to ready/conditional/rework verdict. |
| Lift risk with boundary penalties | Penalize large arc span, weak thickness/air-gap margin, low segment count, and high tip speed. | Risk score and explicit boundary-note set. |
| Map to action path | Translate verdict into immediate next step: annotate, simulate, or rework input assumptions. | Actionable checklist instead of a raw label. |
| Metric | Screening window | Why it matters |
|---|---|---|
| Arc angle | 20-70 deg preferred, 71-120 deg conditional, >120 deg rework | Evidence-backed direction sensitivity exists for large arc magnets; this numeric window is still a stage-1 heuristic and not a release standard. |
| Thickness / air-gap ratio | >=7 preferred, 4-6.99 conditional, <4 rework | Internal screening heuristic for leakage margin. No reliable public universal cutoff was found; keep as provisional checker logic only. |
| Coverage ratio (arc length / pole pitch) | 0.75-1.05 preferred, 0.6-0.74 or 1.06-1.2 conditional, else rework | IEEE evidence shows slot/pole and fringing dependence; this range is a practical pre-check window, not a topology-agnostic rule. |
| Segment count (for segment-parallel mode) | >=8 preferred, 5-7 conditional, <=4 rework | Sensors 2014 shows eight segments much closer to ideal than low-segment cases; keep this as approximation guidance, then verify in model/test. |
| Tip speed | <=65 m/s preferred, 66-90 m/s conditional, >90 m/s rework | High-speed PM literature often exceeds 50 m/s and can approach ~200 m/s; 65 m/s here is conservative screening, not universal rejection. |
| Concept boundary | Valid when | Not valid when | Execution implication | Evidence |
|---|---|---|---|---|
| Material-grade standard vs assembly-level field validity | Use IEC 60404-8-1 and 60404-5 to verify material-property minima and measurement method traceability. | Do not treat those standards as proof that assembled air-gap field distribution is already correct. | Keep material compliance and machine-level field validation as two separate gates. | S6, S7 |
| 2D low-frequency FEMM model scope | Useful for 2D planar/axisymmetric low-frequency screening with explicit boundary and magnetization assumptions. | Not a direct replacement for full 3D multiphysics behavior in axial leakage, structural, thermal, and manufacturing variability. | Escalate to 3D or experimental validation when geometry or duty cycle breaks 2D assumptions. | S2, S3 |
| Segmented-parallel approximation | Works as a practical approximation when segment count is sufficient and air-gap assumptions are documented. | Low segment counts can cause non-trivial radial-component loss and stronger tangential effects. | Treat low-segment layouts as conditional/rework until quantified by simulation or test. | S4 |
| Coverage ratio / pole-arc interpretation | Coverage can be used as an early screening proxy with slot/pole context. | No public evidence supports one global pass/fail ratio across all slot-pole combinations and objectives. | Keep ratio thresholds as local heuristics and force topology-specific verification. | S5 |
| Common claim | Counterexample | Limit condition | Evidence |
|---|---|---|---|
| Any clean-looking radial sketch is simulation-ready. | FEMM examples show constant direction on large arc magnets can differ from true radial direction behavior. | Direction representation error can be introduced even before mesh/solver setup. | S2 |
| Few segments are usually enough for radial-equivalent behavior. | Sensors 2014 shows force-normalized response at two segments is 0.64 versus ideal, while eight/twelve segments are much closer. | Segment choice can dominate force and field-component behavior. | S4 |
| One coverage ratio threshold can fit all machines. | IEEE 2000 shows optimal pole-arc ratio depends on slot/pole pairings and fringing correction. | Topology dependence prevents universal pass/fail ratio without context. | S5 |
| Material standard compliance means field diagram risk is closed. | IEC 60404 series addresses material properties and measurement methods, not full assembly-level field performance. | Still need machine-level electromagnetic and mechanical validation. | S6, S7 |
| Mode | Best for | Strength | Tradeoff |
|---|---|---|---|
| Radial | Radial-flux motor air-gap field targets | Highest directional clarity for motor-oriented field sketches | Manufacturing and cost constraints may increase for some geometries |
| Circumference | Specific coupler/sensor context or simplified communication drafts | Easy to annotate for concept-level discussions | Can misrepresent radial-uniformity goals in motor use-cases |
| Segment-parallel | When radial manufacturing route is constrained but segmentation is available | Provides a practical bridge between concept and manufacturable layouts | Low segment counts can create non-trivial approximation error |
| Option | Speed | Explainability | Traceability | Risk |
|---|---|---|---|---|
| Static image/blog diagram | Fast | Low | Low | Hidden assumptions; easy to misuse in RFQ handoff |
| This checker + report (current page) | Medium | High | High | Still stage-1; must be followed by full simulation and testing |
| Full multiphysics simulation workflow | Slow | High | High | Higher cost/time; requires validated input model and test loop |
| Risk | Impact | Probability | Mitigation |
|---|---|---|---|
| Misusing concept diagram as simulation-equivalent model | High | Medium | When goal is FEA-ready, require explicit material curve, boundary condition, and mesh assumptions before sign-off. |
| Mode alias confusion in procurement communication | High | High | Attach checker output with mode naming, segment count, and diagram legend directly in RFQ packet. |
| Ignoring high-speed retention and thermal coupling limits | High | Medium | Treat high tip-speed verdict as conditional until mechanical retention and thermal analysis gates are complete. |
| False confidence from single-source reference | Medium | Medium | Cross-check at least one independent method source plus one application-specific validation source. |
| Trigger condition | Risk | Tradeoff | Minimum action | Evidence |
|---|---|---|---|---|
| Arc angle is high or mode mismatch appears in checker notes | Field direction misinterpretation during FEA setup and RFQ communication. | Faster drafting vs higher rework probability later in simulation cycle. | Lock magnetization wording in drawing + rerun with radial and segmented alternatives before sign-off. | S2, S4 |
| Coverage ratio leaves preferred band | Local flux/cogging interpretation can drift from intended operating objective. | Aggressive pole-arc loading vs torque ripple/cogging control margin. | Treat as heuristic breach and run topology-specific FEA sweep rather than hard reject/accept. | S5 |
| Tip speed exceeds conservative 65 m/s trigger | Mechanical retention and thermal coupling risk dominates diagram-only certainty. | Higher power density aspirations vs stronger structural and thermal validation burden. | Move result to conditional until sleeve/retention and thermal model gates pass. | S8 |
| Program moves from concept drawing to sourcing decision | Supply concentration or export controls can invalidate assumed material availability/timing. | Best magnetic grade target vs procurement resilience and lead-time predictability. | Attach dual-source and substitution fallback to RFQ when dependence on a single chain is high. | S9, S10 |
Scenario A: 8-segment radial motor rotor draft
Assumption: OD 96 mm, ID 74 mm, arc 58 deg, radial mode, 8 segments, FEA-ready goal.
Outcome: Usually lands in ready/conditional boundary; next step is simulation with explicit material and boundary conditions.
Scenario B: circumference mode with radial-flux target
Assumption: Same geometry, but circumference mode and strict radial uniformity requirement.
Outcome: Often downgraded to conditional/rework due to direction mismatch risk in motor air-gap targets.
Scenario C: low segment count fallback
Assumption: Segment-parallel mode with <=4 segments and high tip speed.
Outcome: Typically rework unless segmentation, margin, or use-case scope is adjusted.
| Topic | Status | Reason / recovery path |
|---|---|---|
| Universal pass/fail threshold across all arc magnet geometries | Pending confirmation | No reliable public unified data supports one global threshold that is valid for every motor topology and duty cycle. |
| One-to-one mapping from catalog wording to simulation-ready direction model | Pending confirmation | No reliable public unified naming map exists; catalog terms remain inconsistent across suppliers and require clarification per drawing package. |
| Universal tip-speed pass/fail boundary for all PM rotor structures | Pending confirmation | Public literature reports broad operating envelopes; no single speed cutoff is reliable across topology, sleeve, and duty-cycle constraints. |
| Open dataset for failure-rate by magnetization mode under matched geometry | Limited | Public data is sparse and usually study-specific; validation must be project-specific. |
| ID | Source | How used | Date context | Link |
|---|---|---|---|---|
| S1 | Brave SERP sample for keyword intent | Intent pattern validation: confirms mixed practical + explanatory demand requiring hybrid tool/report structure. | Checked May 25, 2026 | Open source |
| S2 | FEMM radial magnetization note | Shows direction-model risk on large arc magnets and clarifies radial vs constant magnetization definition. | Last modified 2026-05-03 | Open source |
| S3 | FEMM User Manual v4.2 | Defines 2D planar/axisymmetric low-frequency scope and boundary-condition context for this checker layer. | Manual date 2015-10-25 | Open source |
| S4 | Sensors (2014) segmented NdFeB study | Provides quantified segment-count effects (e.g., 2-segment, 8-segment, 12-segment normalized force comparison). | Published 2014-07-21 | Open source |
| S5 | IEEE Transactions on Energy Conversion (2000) | Shows pole-arc optimization dependence on slot/pole combinations and fringing correction factors. | Published 2000-12 | Open source |
| S6 | IEC 60404-8-1:2023 | Defines permanent-magnet material property minima and dimensional tolerances (material-level scope). | Publication date 2023-09-20 | Open source |
| S7 | IEC 60404-5:2015 | Defines measurement methods for magnetic properties and demagnetization/recoil characterization. | Publication date 2015-04-16 | Open source |
| S8 | Machines (2022) high-speed PM motor review | Adds context for circumferential speed ranges and why fixed speed thresholds need conservative interpretation. | Published 2022-07-07 | Open source |
| S9 | USGS Mineral Commodity Summaries 2026 (Rare Earths) | Procurement-risk context for material and supply assumptions in late-stage diagram-to-RFQ transitions. | Published February 2026 | Open source |
| S10 | IEA Global Critical Minerals Outlook 2025 (revised 2026) | Adds concentration-risk context when users extend diagram decisions into sourcing decisions. | Report year 2025, accessed May 2026 | Open source |
Required package: OD/ID/arc/thickness, air-gap assumption, Br grade target, and thermal envelope.
Include mode wording exactly as used in your drawing to avoid alias mismatch in procurement and simulation handoff.