We built a 1000 watt wind turbine to help charge the battery bank that powers our offgrid home. It's a permanent magnet alternator, generating 3 phase ac, rectified to dc, and fed to a charge controller. The magnets spin with the wind, the coils are fixed, so no brushes or slip rings necessary.

Update: DIY Amp Hour meter for monitoring charge!

All about homebrew wind and offgrid power systems, the complete reference!

Step 1: Build the Magnet Disks

We had 12" steel disks hydro cut. We cut a template for mounting the magnets. Then we mounted 12 grade n50 magnets around the outside edge. We then built a form, and poured the resin with hardner.

Step 2: Build the Coil Disk

We wound the nine individual coils, soldered them in a 3 phase wye configuration, and encased them in resin. We used 35 turns of 2 parallel strands of 14 gauge enameled (magnet) wire for 12 volts. Use 70 turns of single strand for 24 volts. # 3 phase diagram shown here shows 3 stator coils. each of those coils is actually 3 coils in series. coils 1,4, and 7 are series together, 2,5, and 8 are series together, and 3,6, and 9 are series together.

more details, see the following page 15 for the series star, 1-y diagram.

http://groups.yahoo.com/neo/groups/axialflux/files

AXIAL_FLUX_HowItWorks.pdf