Ran the three coils in series, in phase, to make a nice big output voltage.
I make 60ish DC volts at 3000rpm idle.
I ran a single full-wave rectifier into a 2200uF capacitor to get this result. Hardly any ripple with no load (AC measured around 0.5V at idle).
Managed to rather quickly let the magic smoke out of a 10ohm, 10W test resistor, at 15.5V measured voltage at idle. Makes sense, that's 24W.
I've got an adjustable voltage regulator coming, I should probably rewire the stator to make less voltage, though. Guess I'll switch to a parallel setup, should still make about 20V at idle but with 3x as much current. The regulator I'm getting is limited to about 40V input, so that should work out well. And I still have room for one more coil, should I run out of power.
More test results coming soon!