Best Copper Wire Gauge for Wind Turbine PM Generator With 50x20x10 Magnets?

I have young man who is developing a generator. He needs to know the best gauge copper wire to use with a 50x20x10 magnet config.

He is using it on a wind turbine and is worried about high winds causing RPMs to rise and how it may affect the copper temp etc. The generator is a non ferrous construction.

He really needs some help in the electrical department I think

A rule-of-thumb for transformers that should apply to a generator (which is a rotating transformer) is that the wire size should be 700 circular mils per amp. A circular mil is equal to the wire diameter in mils (thousandths of an inch) squared. For example, American Wire Gage size #12 has a diameter of 80.8 mils and and this gives 6530 circular mils. At 700 circular mils per amp this wire can be safely used at 6530/700 = 9 amps.