{
 "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": "dc-motor-390-size",
 "name": "390 size brushed DC motor: Ø27.6 × 47 mm, Ø2.3 shaft",
 "kind": "hardware",
 "category": "Electronics",
 "group": "Motors",
 "year": null,
 "question": "What are the dimensions of a 390 size DC motor?",
 "tags": [
  "390",
  "395",
  "dc motor",
  "brushed motor",
  "motor",
  "motor envelope",
  "stirling"
 ],
 "aliases": [
  "390 motor dimensions",
  "rs-390 size",
  "390 motor mounting holes",
  "390 motor step",
  "390 dc motor stl"
 ],
 "overall_mm": {
  "length": null,
  "width": null,
  "height": null
 },
 "official_cad": false,
 "xem_status": "free-files",
 "les": false,
 "free_files": 1,
 "url": "https://xemstudio.com/objects/dc-motor-390-size/",
 "sheet_txt": "https://xemstudio.com/objects/dc-motor-390-size/sheet.txt",
 "sheet": {
  "basis": "Sigmanortec 390 motor listing (no maker's drawing found). Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.",
  "overall_mm": {
   "length": null,
   "width": null,
   "height": null
  },
  "notes": [
   "Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.",
   "The can is Ø27.6 × 47 mm, not counting the bearing sleeves at each end.",
   "The Ø2.3 shaft is 14 mm from the face, 11 of it beyond the 3 mm front sleeve. The sleeves' diameter is not listed, so they are not drawn.",
   "Two 2.5 mm screw holes 16 mm apart in the face (the same spacing as the 380 family), drawn 2.0 deep only to mark them; the listing gives no thread or depth.",
   "Terminal tabs and the wire exit are not drawn. Only one listing gave these sizes; check the motor in hand.",
   "In DIY Stirling builds, brushed DC motors of this kind are turned by the engine and used as a generator (an LED, a resistor or a meter across the leads) or as a load on the flywheel shaft."
  ],
  "table": {
   "columns": [
    "feature",
    "mm",
    "from"
   ],
   "rows": [
    [
     "can",
     "Ø27.6 × 47 (without sleeves)",
     "Sigmanortec"
    ],
    [
     "shaft",
     "Ø2.3",
     "Sigmanortec"
    ],
    [
     "shaft from the face",
     "14 (11 beyond the sleeve)",
     "Sigmanortec"
    ],
    [
     "front sleeve height",
     "3",
     "Sigmanortec (14 − 11)"
    ],
    [
     "face holes",
     "2 × Ø2.5 on 16",
     "Sigmanortec"
    ]
   ]
  }
 },
 "sheet_text": "390 size brushed DC motor: Ø27.6 × 47 mm, Ø2.3 shaft — dimension sheet\nSource: Xem Studio, https://xemstudio.com/objects/dc-motor-390-size/  (CC BY 4.0)\nBasis: Sigmanortec 390 motor listing (no maker's drawing found). Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.\nCatalog version: 2026-10-20\n\nSizes: see table below\n- Envelope only: the outside of the motor at its published sizes. The windings, magnets, brushes and bearings inside are not drawn.\n- The can is Ø27.6 × 47 mm, not counting the bearing sleeves at each end.\n- The Ø2.3 shaft is 14 mm from the face, 11 of it beyond the 3 mm front sleeve. The sleeves' diameter is not listed, so they are not drawn.\n- Two 2.5 mm screw holes 16 mm apart in the face (the same spacing as the 380 family), drawn 2.0 deep only to mark them; the listing gives no thread or depth.\n- Terminal tabs and the wire exit are not drawn. Only one listing gave these sizes; check the motor in hand.\n- In DIY Stirling builds, brushed DC motors of this kind are turned by the engine and used as a generator (an LED, a resistor or a meter across the leads) or as a load on the flywheel shaft.\n\nfeature  mm  from\ncan  Ø27.6 × 47 (without sleeves)  Sigmanortec\nshaft  Ø2.3  Sigmanortec\nshaft from the face  14 (11 beyond the sleeve)  Sigmanortec\nfront sleeve height  3  Sigmanortec (14 − 11)\nface holes  2 × Ø2.5 on 16  Sigmanortec\n\nFiles elsewhere (not hosted by Xem Studio; license as stated by the publisher):\n- Sigmanortec: 390 motor listing: Ø27.6, 47 long without the bearing sleeves, shaft Ø2.3 × 14 (11 beyond the sleeve), 2.5 mm screw holes 16 mm apart — web — listing [verify license at link] — https://sigmanortec.ro/en/motor-390-6-24v-13000rpm-shaft-23x14mm\n\nFree files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/dc-motor-390-size/index.json\nAPI: https://xemstudio.com/api/geometry?object=dc-motor-390-size\n",
 "sources": [
  {
   "publisher": "Sigmanortec",
   "title": "390 motor listing: Ø27.6, 47 long without the bearing sleeves, shaft Ø2.3 × 14 (11 beyond the sleeve), 2.5 mm screw holes 16 mm apart",
   "url": "https://sigmanortec.ro/en/motor-390-6-24v-13000rpm-shaft-23x14mm",
   "formats": [
    "web"
   ],
   "license": "listing",
   "license_verified": false,
   "hosted": false
  }
 ],
 "xem": {
  "status": "free-files",
  "sheet_free": true,
  "mesh_price_usd": null,
  "step_price_usd": null,
  "tolerance_mm": null
 },
 "related": [
  "dc-motor-380-size",
  "dc-motor-365-size",
  "dc-motor-540-size"
 ],
 "fits": [
  {
   "role": "Alternatives",
   "items": [
    {
     "slug": "dc-motor-380-size",
     "why": "same 16 mm face holes, 37.8 can"
    }
   ]
  },
  {
   "role": "Also needed",
   "items": [
    {
     "slug": "leds-tht",
     "why": "an LED across the leads shows generator output"
    }
   ]
  }
 ],
 "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": "shaft",
   "exact": "Ø2.3",
   "mates": "pinion or pulley bore (pressed on)",
   "fit": "press",
   "files": "dc-390-"
  },
  {
   "feature": "mounting holes",
   "exact": "2 × Ø2.5 on 16 (drawn 2.0 deep as position marks)",
   "mates": "screws through the mount",
   "fit": "designed",
   "files": "dc-390-"
  },
  {
   "feature": "can",
   "exact": "Ø27.6",
   "mates": "cradle",
   "fit": "socket",
   "files": "dc-390-"
  }
 ],
 "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": "What are 390 motor dimensions?",
   "a": "About Ø27.6 × 47 mm without the sleeves, Ø2.3 shaft 14 mm from the face, two 2.5 mm screw holes 16 mm apart (one seller's listing)."
  },
  {
   "q": "Do 380 mounts fit a 390?",
   "a": "The face hole spacing is the same 16 mm and the can Ø is within 0.1 mm; the 390 can is about 9 mm longer."
  }
 ],
 "files_license": null,
 "offers": [
  {
   "file": "dc-390-size",
   "formats": [
    "step",
    "stl"
   ],
   "price_usd": 0,
   "license": "CC BY 4.0 (Xem Studio)",
   "step": "https://xemstudio.com/files/hardware/dc-motor-390-size/dc-390-size.step",
   "stl": "https://xemstudio.com/files/hardware/dc-motor-390-size/dc-390-size.stl",
   "note": "390 size envelope: Ø27.6 × 47 can, Ø2.3 shaft 14 from the face, two Ø2.5 screw holes on 16 (2.0 deep position marks)"
  }
 ],
 "markdown": "https://xemstudio.com/objects/dc-motor-390-size/index.md"
}