Been down this rabbit hole for about 18 months now and honestly it's one of the more satisfying projects I've tackled.
I'm running a rewound induction motor from an old Hotpoint (rescued from the tip) as a permanent magnet alternator. Rewinding is the tricky bit — you need to strip the original windings and wind new coils around neodymium magnets that you bond onto the rotor. Plenty of YouTube tutorials but they vary massively in quality, so be selective.
A few things I've learned the hard way:
- Cut-in speed matters enormously — get your pole count wrong and you'll need 40mph gusts before it generates anything useful
- Rectification — I'm using a simple 3-phase bridge rectifier before it hits my Victron MPPT. Works surprisingly well
- Blade balance is absolutely critical. Even slight imbalance will eventually shake your tower apart or wreck the bearings
- Cogging torque — some motors have terrible cogging which kills performance in low winds. Worth testing before you commit hours of rewinding time
Output is modest — maybe 200-300W in a decent Welsh blow — but for zero outlay on the alternator itself it's hard to argue with.
Anyone else experimented with different motor sizes? I'm wondering whether a bigger drum motor from a commercial washer would be worth chasing down. Also curious whether anyone's tried axial flux builds versus this radial approach — seems like axial flux is theoretically cleaner but the fabrication complexity is considerably higher.
What are your setups like? Tower height, blade diameter, that sort of thing. Always keen to compare notes.
