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Linear alternator housing for Ø80 and Ø100 flexures (2 in / 3 in)
What housing holds the linear alternator stator on a free-piston engine? · Hardware · basis: Rim screw circle of the flexure head (R35.2 for Ø80, R44 for Ø100 flexures); sleeve pocket at Ø60.5; M3 clearance Ø3.4
Long Earth Society build part. Power take-off on the LES free-piston test bed. The engines
Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features
- sizes
- 2 in table
Notes
- The stator body: a Ø63.7 barrel 36 tall between a base flange and a top flange (Ø96 for the 2 in, Ø116 for the 3 in), each 4 thick.
- From the top, a Ø60.5 pocket (fit: socket) takes the back-iron sleeve on a 2 mm ledge; a Ø40 passage lets the Ø35 mover through without contact; a 2.5 × 3 slot lets the leads out.
- 3 × Ø3.4 holes on the flexure head's rim circle (R35.2 or R44) bolt it to standoffs above flexure stack A; the coil centre sits 21 mm above its underside.
Sizes
| file | flexure | flanges | rim circle | height | sleeve pocket | mover passage |
|---|---|---|---|---|---|---|
| alt-housing-2in-flex80 | Ø80 (2 in) | Ø96 × 4 | R35.2 | 36 | 60.5 | 40 |
| alt-housing-3in-flex100 | Ø100 (3 in) | Ø116 × 4 | R44 | 36 | 60.5 | 40 |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| sleeve pocket | Ø60.5 | back-iron sleeve OD | socket | alt-housing-* |
| housing rim holes | Ø3.4 | M3 screw clearance | designed | alt-housing-* |
| mover passage | Ø40 | Ø35 mover (no contact) | designed | alt-housing-* |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| NASA (NTRS, public domain) | Linear alternator design for free-piston Stirling convertors (2005) | US Government work, public domain | |
| NASA (NTRS, public domain) | Sunpower/NASA 80 We free-piston Stirling convertor (2002) | US Government work, public domain | |
| Wikipedia | Linear alternator | web | CC BY-SA 4.0 (text) |
| Wikipedia | Free-piston engine | web | CC BY-SA 4.0 (text) |
| Long Earth Society | Engine builds | web, video | LES site |
Free files
★ Free files 2 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| alt-housing-2in-flex80 | 2in housing: Ø96 base and top flanges with 3 × M3 on the R35.2 rim circle (same as the flexure head), pocket for the back-iron sleeve on a 2 mm ledge, Ø40 mover passage, lead slot; 36 tall | STEP · STL |
| alt-housing-3in-flex100 | 3in housing: Ø116 base and top flanges with 3 × M3 on the R44 rim circle (same as the flexure head), pocket for the back-iron sleeve on a 2 mm ledge, Ø40 mover passage, lead slot; 36 tall | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=linear-alternator-housing
How it fits
Goes in or on
Tri-clamp flexure headon standoffs on the flexure head's rim screwsConnects to
Linear alternator back-iron sleeve Ø60.5 × Ø52.5…sleeve in the Ø60.5 pocket
Linear alternator cap ring, Ø96 and Ø116cap on the top flangeAlso needed
Threaded standoffs, M2.5 and M3M3 × 30 standoffs
Socket head cap screws, M2–M8M3 × 10 / 12 / 16In these build lists
Free-piston Stirling, 2 in tri-clampNo crank: piston and displacer each hang on a stack of spiral flexures, with a t…You might also need
Questions
How does the linear alternator mount on the free-piston engine?
Its base flange sits on 3 × M3 × 30 standoffs above flexure stack A, on the flexure head's rim circle (R35.2 for 2 in).
Does it fit a 1.5 in engine?
No: the Ø60 flexures of the 1.5 in engine are too small for this stator.