{
 "version": "2026-10-20",
 "license": "Dimension sheets are written by Xem Studio from the cited sources and are free to use (CC BY 4.0, attribute 'Xem Studio'). Linked files belong to their publishers under the license shown; Xem Studio does not host them. 'license_verified: false' means the license shown is from memory or the publisher's page as last read and should be confirmed at the link before commercial use.",
 "slug": "axial-flux-stator",
 "name": "Axial-flux stator plates: Ø90 9-coil and Ø70 6-coil",
 "kind": "hardware",
 "category": "Stirling engines",
 "group": "Generators & instruments",
 "year": null,
 "question": "How do I wire a 9-coil 3-phase axial flux stator?",
 "tags": [
  "axial flux",
  "stator",
  "coil",
  "3-phase",
  "generator",
  "stirling",
  "long earth society"
 ],
 "aliases": [
  "axial flux stator",
  "9 coil stator 3 phase",
  "12 pole 9 coil generator",
  "stator plate stl",
  "coreless stator"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": true,
 "free_files": 2,
 "url": "https://xemstudio.com/objects/axial-flux-stator/",
 "sheet_txt": "https://xemstudio.com/objects/axial-flux-stator/sheet.txt",
 "sheet": {
  "basis": "Coreless 3-phase stator: coils = 3/4 of poles (12 pole / 9 coil, 8 pole / 6 coil), Ø13 pockets for the bobbin flanges, M3 holes at ISO 273 clearance",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "The Ø90 stator is a 4 mm plate with 9 Ø13 through pockets on a Ø72 circle, a Ø14 centre hole the Ø8 shaft passes without contact, and 3 × Ø3.4 (M3) mounting holes on a Ø86 circle.",
   "The Ø70 stator has 6 Ø13 pockets on a Ø52 circle, the same Ø14 centre hole and 3 × Ø3.4 holes on a Ø66 circle.",
   "The pockets take the Ø13 flanges of the coil bobbin (slide).",
   "Wire 3-phase by series groups: on 9 coils 1-4-7, 2-5-8, 3-6-9; on 6 coils 1-4, 2-5, 3-6; rectify with a 3-phase bridge."
  ],
  "table": {
   "columns": [
    "stator",
    "plate_mm",
    "coils",
    "coil_circle_mm",
    "centre_hole_mm",
    "mount_holes"
   ],
   "rows": [
    [
     "stator-90-9coil",
     "Ø90 × 4",
     9,
     72,
     14,
     "3 × Ø3.4 on Ø86"
    ],
    [
     "stator-70-6coil",
     "Ø70 × 4",
     6,
     52,
     14,
     "3 × Ø3.4 on Ø66"
    ]
   ]
  }
 },
 "sheet_text": "Axial-flux stator plates: Ø90 9-coil and Ø70 6-coil — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/axial-flux-stator/  (CC BY 4.0)\nBasis: Coreless 3-phase stator: coils = 3/4 of poles (12 pole / 9 coil, 8 pole / 6 coil), Ø13 pockets for the bobbin flanges, M3 holes at ISO 273 clearance\nCatalog version: 2026-10-20\n\nSizes: see table below\n- The Ø90 stator is a 4 mm plate with 9 Ø13 through pockets on a Ø72 circle, a Ø14 centre hole the Ø8 shaft passes without contact, and 3 × Ø3.4 (M3) mounting holes on a Ø86 circle.\n- The Ø70 stator has 6 Ø13 pockets on a Ø52 circle, the same Ø14 centre hole and 3 × Ø3.4 holes on a Ø66 circle.\n- The pockets take the Ø13 flanges of the coil bobbin (slide).\n- Wire 3-phase by series groups: on 9 coils 1-4-7, 2-5-8, 3-6-9; on 6 coils 1-4, 2-5, 3-6; rectify with a 3-phase bridge.\n\nstator  plate_mm  coils  coil_circle_mm  centre_hole_mm  mount_holes\nstator-90-9coil  Ø90 × 4  9  72  14  3 × Ø3.4 on Ø86\nstator-70-6coil  Ø70 × 4  6  52  14  3 × Ø3.4 on Ø66\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Wikipedia: Axial flux motor — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Axial_flux_motor\n- Wikipedia: Alternator — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Alternator\n- Hugh Piggott: A Wind Turbine Recipe Book (axial-flux alternator design) — web, PDF — Author's site [verify license at link] — http://scoraigwind.co.uk/\n- Long Earth Society: Engine and rig builds — web, video — LES site — https://longearthsociety.com/engineering/\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 2 parts): https://xemstudio.com/files/hardware/axial-flux-stator/index.json\nAPI: https://xemstudio.com/api/geometry?object=axial-flux-stator\n",
 "sources": [
  {
   "publisher": "Wikipedia",
   "title": "Axial flux motor",
   "url": "https://en.wikipedia.org/wiki/Axial_flux_motor",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Wikipedia",
   "title": "Alternator",
   "url": "https://en.wikipedia.org/wiki/Alternator",
   "formats": [
    "web"
   ],
   "license": "CC BY-SA 4.0 (text)",
   "license_verified": true,
   "hosted": false
  },
  {
   "publisher": "Hugh Piggott",
   "title": "A Wind Turbine Recipe Book (axial-flux alternator design)",
   "url": "http://scoraigwind.co.uk/",
   "formats": [
    "web",
    "PDF"
   ],
   "license": "Author's site",
   "license_verified": false,
   "hosted": false
  },
  {
   "publisher": "Long Earth Society",
   "title": "Engine and rig builds",
   "url": "https://longearthsociety.com/engineering/",
   "formats": [
    "web",
    "video"
   ],
   "license": "LES site",
   "license_verified": true,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "axial-flux-rotor",
  "coil-bobbin",
  "hall-sensor-mount",
  "socket-head-cap-screws-metric"
 ],
 "fits": [
  {
   "role": "Connects to",
   "items": [
    {
     "slug": "coil-bobbin",
     "why": "Ø13 bobbin flanges in the Ø13 pockets (slide)"
    },
    {
     "slug": "socket-head-cap-screws-metric",
     "why": "M3 through the Ø3.4 mounting holes"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "axial-flux-rotor",
     "why": "magnets on the same Ø72 / Ø52 circle"
    }
   ]
  }
 ],
 "dimensions": "exact (nominal, no printing tolerance)",
 "dimension_rule": "All geometry on Xem Studio is exact (nominal, true size) with no printing tolerance. Where a part meets another part, the object lists its mating features (feature, exact size, what it mates with, fit class: press, slide, run, socket, clamp or designed). Apply your process's allowance to those features only; 'designed' gaps are part of the design and stay as drawn.",
 "mating": [
  {
   "feature": "centre hole",
   "exact": "Ø14",
   "mates": "shaft passes clear (no contact)",
   "fit": "designed",
   "files": "stator-"
  },
  {
   "feature": "coil pockets",
   "exact": "Ø20",
   "mates": "bobbin flange Ø20",
   "fit": "slide",
   "files": "stator-"
  },
  {
   "feature": "mounting holes",
   "exact": "Ø3.4",
   "mates": "M3 screw clearance",
   "fit": "designed",
   "files": "stator-"
  },
  {
   "feature": "coil-to-rotor air gap",
   "exact": "1.5 each side (8 stator and bobbin, rotor faces 11 apart)",
   "mates": "rotor magnet face",
   "fit": "designed",
   "files": "stator-"
  }
 ],
 "fit_classes": {
  "press": "stays put: pin, tube, bearing or magnet held by interference. Typical FDM: hole +0.0 to +0.1 mm on diameter.",
  "slide": "assembles by hand and is held by a grub, pinch or clamp: shaft in a hub, rod in a socket, spigot in a bore. Typical FDM: +0.2 mm.",
  "run": "turns or slides in use: pin in a link, rod through a guide. Typical FDM: +0.3 mm.",
  "socket": "large sliding fit: syringe barrel, sleeve, bobbin in a bore. Typical FDM: +0.3 mm.",
  "clamp": "split part that closes on the mating part with screws: make it at size.",
  "designed": "a gap that is part of the design (piston fit option, displacer gap, air gap): do not change."
 },
 "faq": [
  {
   "q": "How do I wire a 9-coil stator for 3-phase?",
   "a": "Coils 1-4-7, 2-5-8 and 3-6-9 each in series as the three phases, then a 3-phase bridge rectifier."
  },
  {
   "q": "Does the shaft touch the stator?",
   "a": "No; the centre hole is Ø14 around the Ø8 shaft, so the stator is fixed to the frame by its three M3 holes."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "stator-90-9coil",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/stator-90-9coil.step",
   "stl": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/stator-90-9coil.stl",
   "note": "stator plate Ø90 × 8: 9 Ø20 coil pockets on a 66 mm circle (3-phase, 12 pole / 9 slot), Ø14 centre hole (shaft passes clear), 3 × Ø3.4 (M3 clearance) mounting holes on an 82 mm circle (2.3 mm wall to the rim)"
  },
  {
   "file": "stator-70-6coil",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/stator-70-6coil.step",
   "stl": "https://xemstudio.com/files/hardware/axial-flux-generator-kit/stator-70-6coil.stl",
   "note": "stator plate Ø70 × 8: 6 Ø20 coil pockets on a 46 mm circle (8 pole / 6 slot), Ø14 centre hole, 3 × Ø3.4 mounting holes on a 62 mm circle (2.3 mm wall to the rim)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/axial-flux-stator/index.md"
}