Water pumping windmills, with rotor diameters ranging from 6-16 feet are still manufactured. Because of their many blades, only a gentle breeze is necessary to start and run them. Though they cannot take advantage of teh large amounts of power in heavy winds, they are quite adequate for supplying the water needs fora small farm 500 to 5,000 gallons a day depending on the size of the unit and the depth of the well. Protection against extreme winds is provided in various ways:
- The tail vane automatically turns sideways to keep the rotor facing at right angles to the wind
- Brakes are automatically applied
- The mil may be automatically decoupled from the pump shaft.
The only attention the windmill needs is replacement of teh oil in the gear case once a year.
