Another ferrite magnet alternator project. This one is on the Backshed discussion board hosted by Glenn ‘Gizmo’.
The stator is supported at the centre, which is a bit more compact but the supporting bolts between magnet rotors restrict the overall size, and the stator mounts are more critical. My first ever pma was a bit like this, and I have been thinking about posting about that one day too.
The stator is really quit a beautiful if delicate thing:
12V cut-in is at 170 rpm. Glenn used 132 turns of 0.91mm wire in each coil and then connected the phases series/parallel in pairs. The 3 phases are wired star/wye. I would not expect it to be able to sustain more than about 2-300 watts for long periods.
The magnets (which are surprisingly long) seem to be held in place with plywood.