Catching the Wind
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Self-oiling mills were available in the early 1900s, which replaced frequent greasing with one-time annual maintenance. To service the self-oiling mills, first the oil was drained. Then the settlings were cleaned out in the motor bowl and a quart or two of very light non-detergent oil added. For some reason, that same variety of oil is used in windmills today, and contaminants still settle to the bottom and grind up bearings and gears through time.
From early on, windmill governors were a big problem. Some farmers tried to change the pitch on the blades in response to wind speed, while other farmers used counter weights. Still others used a small tail tightly mounted to force the fan out of the wind. Finally, farmers discovered that setting the mill offset from the pivot point was the easiest fix. This technique allows the wind to push the fan blades out of the wind's direct force, and solved the speed problem.
In most windmills made after 1900, a spring from the tailbone to the motor acts as the governor. Holes in the tail-bone stretched the spring tight and kept the fan facing more directly into the wind. Conversely, lighter tension allowed the fan to run at a better angle to the wind. This simple method works, and if the spring breaks, the fan nearly turns to a right angle to the wind direction, either motoring slowly or shutting off with no damage. Some common mills that utilize this feature include Dempster, Baker, Fairbury and Aermotor varieties. The results are amazing, and the Aermotor Model 602, with its 6-foot fan, can run at 125 rpm and 40 strokes per minute.
Catching and restoring windmills may be difficult, but it's easy to release an old mill back into the sky. We simply assembled it on the ground, then we picked it up with the crane and bridle so the mill hung almost vertically above the holes we dug for its legs. Then we bolted anchor sections to the tower's legs, and set it in place so that the tower is leveled and earth is tamped back solidly over the four holes above each anchor plate. Finally, the restored windmill is again ready to work in the wind.
- Jim and his wife, Joan, operate Little Village Farm at 47582 240th St., Dell Rapids, SD 57022. Contact them at (605) 428-5979.
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