I know this is an old post, but I started it so I will see if I can finish it. After a shoulder and a knee replacement and other old guy health issues, I feel good enough to continue the build. I have the magnets installed on the rotor, and am in the process of winding the coils. I wound a test coil with 10 rounds and at 200 rpm's, I get 3.16 volts AC. I have 24 poles and will be using 18 coils wired star.
I have a few questions. The first is, what would be a safe operating rpm for a 20 foot diameter mill? I had the rotor up to 400 rpm on the test stand and there is no vibration. Of course, that is without the blades on.
The second question is, what would be the AC voltage between the phases at 200 rpm's? I think I know the answer, but just want to double check.
3.16 volts AC x 1.74 x 6 coils in series =32.99 volts AC between phases. I am hoping to wind the coils with #14 gauge wire, two in hand, 100 turns, which will give me 50 turns of #11 gauge wire. 50 turns/10 turns of test coils =5 x 32.99 volts AC=164.95 volts AC per phase. I am trying for around 240-300 volts AC, but that all depends how high I can safely run the rpm's.