If we are talking about a car/truck alternator with separate field control, I have a suggestion. A number of years ago you could buy a kit that would apply full battery voltage to the alternator at a flip of a switch, while also disconnecting the vehicle battery. Then, when the engine was cranked up to 2500 rpm or so, the alternator is spinning at app. 6000 rpm, and putting out 90vdc or so. The rpm's are not exceeding its normal usage, but the DC voltage was good enuf to operate a universal motor of 1/2 hp or so (leaf blower) at near full power with no bad side effects, except fuel consumption on the prime mover (!). It works; I used it many times for an hour or so at a stretch. Flip the switch, and you are back on the road.
This also idicates the normal alternator, which will put out full charging volts at about 2500 rpm, can be speeded up a bit (50%?) to produce double its voltage output with no other modifications or accessories. If you are trying to obtain this kind of output at wind speed, it obviously is impractical. Good luck.
K3CZ Van, PE