Here is a DIY Project for wind turbine alternator.
The alternator has two 12 inch diameter rotors that each have 12 neodymium disk magnets measuring 1.47 inche in diameter and .6 inches thick. Between the rotors is the stator consisting of 9 coils of awg #20 wire, 200 turns each. The coils are arranged to produce 3-phase ac. Each phase has 3 coils wired in series. There are 3 full wave bridge rectifiers, one for each phase. Each is isolated from the other. All three rectified dc outputs are wired together in parallel and the dc is sent via cable to the battery bank.
The stator is made by sandwiching the coils between two pieces of epoxy fiber glass board, the kind used in the manufacture of printed circuit boards. The top and bottom sheets, each 1/16 inch thick, are held together with bolts. They have reinforcing ribs added for stiffness. Power is brought out by means of stainless steel machine screws.
If you’d like to build one yourself, you must know it can theoretically produce 316W, by the formula:
"Watts = Conversion constant * Betz limit * efficiency * area in sq. m * wind^3
In a perfectly efficient turbine,
Watts = .05472 * 59% * 100% * 4.46 * 13^3 =316 watts"