Rewiring Generators as Alternators

Wind generators run at fairly slow speeds: usually 250 to 600 rpm. Most people who design their own wind systems are stymied by the unavailability of slow speed generators. They usually choose to use an off-the-shelf generator that is stepped up to operating speed from the relatively slow propeller speed of a wind generator. But stepping up with gears, chains or belts introduces large inefficiencies, not to mention more moving components that need maintenance. There is another way around this problem: rewinding the alternator or generator for slow speed operation..

Short ebook - no illustrations but some good information.