windmills and other wind-operated machines, namely, wind electrical power generating units; parts and accessories for the aforesaid goods, namely, mill towers and masts, blades, blade hubs, mill housings, machine beds, yaw rings and gears, adjustment mechanisms for setting the pitch of the wings, brakes, main shafts, universal joints, transmission cases, clutches and electrical generators, reserve electrical power supply units; and, electric motors for windmills