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Linear alternator coil Ø50 × 10 (≈ 314 turns)
How many turns and what size is each coil of the linear alternator? · Hardware · basis: Winding volume of one bobbin bay; turns and resistance computed in the generator for 0.30 mm wire
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
- 6 in table
Notes
- One coil of the alternator, as the solid of its winding: Ø50 outside, Ø38.6 inside (the bobbin core), 10 long.
- About 314 turns of 0.30 mm wire fill it. Two per alternator, the second wound the opposite way; both in series come to about 21.3 Ω.
- At 12 Hz and 12 mm stroke the pair gives about 22.7 V peak per tesla of gap flux.
Sizes
| parameter | value |
|---|---|
| outside | 50 |
| inside | 38.6 |
| length | 10 |
| turns | ≈ 314 of 0.30 mm |
| resistance, both in series | 21.3 Ω |
| EMF per tesla | 22.73 V peak at 12 Hz, 12 mm |
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 |
|---|---|---|---|---|
| coil in its bay | bay volume | bobbin bay | designed | alt-coil-* |
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 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| alt-coil-bay | coil: the winding volume of one bay, Ø50 × 10 (about 314 turns of 0.30 mm wire fill it); two per alternator, the second wound the opposite way | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=linear-alternator-coil
How it fits
Goes in or on
Linear alternator bobbinfills one 10 mm bayConnects to
Linear alternator moverthe magnet row it sits overIn 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 many turns on each linear alternator coil?
About 314 turns of 0.30 mm wire in the Ø50 × 10 bay.
How are the two coils connected?
Wound in opposite directions and joined start-to-start in series: about 21.3 Ω together.