I have a small stream, low head, year round flow - that I want to use for a 12 VDC battery charging application. We use two 200AH batteries to power a 150W load with an inverter at our camp for a few hours every night.
I have a home brewed Pelton setup in a 5 gallon pail, its fed with a 1" well pipe, 15GPM at about 40PSI. I can spin the shaft 950 RPM all day. I believe I have the mechanical part figured out, the drive train, if you will - seems to be pretty stable. I have tried a couple motors, none of them produced enough charging power, so I wound an alternator. I have 6 coils, 20AWG @ 100 turns, wired in a 'Y' to make 3 phase AC. The coils are arranged in a circular pattern with a 4" diameter, each coil has about a 1" center diameter.
I have 8 cylindrical magnets 3/4 diameter and 1/4 thick rated N48. I have the stator mounted on an adjustable base, and I can adjust the gap fairly easily. Even with the magnets very close to the stator, I get less than a volt across any pair of phases when spun by hand at relatively low RPM - my guess is it should be higher . I only have a single rotor, and would prefer to use only one to make the assembly somewhat easier. My question is:
Did I buy magnets that are too small? I want to keep the stator, and I don't mind changing the magnets, although they are somewhat expensive (but not compared to gas for the generator). Any help would be appreciated.
My project is documented here:
http://web.me.com/lroloson/Micro_Hydro/Welcome.html