Check out Ebay for "Gear Reducer". I bought a 10:1 reducer, helical gears, and it will power my 2+ KW wind turbine, by turning it around, and driving the low speed shaft with the blade. Allow for a flex mount to the shafts on the gearbox and generator, and, you are set. No fancy welding and bearing alignments.
Weight is less than 22#, and that includes the cast iron mount, that I plan to do away with, and use Aluminum. It was a Brand new unit, and, I paid $22.00 + S&H, so, total was $34.00.
I used a "Shaft Mount" gear reducer on the 4KW machine, I built in 1979. Never had a minutes worth of trouble, until the Tornado trashed the machine.