Airbrake governer history/operation

Discussion in 'Wind Turbine History' started by Jimmy D., Dec 1, 2011.

  1. The airbrake governer has been used for hundreds, perhaps thousands of years to control excess energy in rotating machinery. For the past 300-400 years, it has been used to regulate the speed of music boxes, chiming clocks, and more recently, wind generators, among other things. The principle is simple. A pair of flaps swing out by centrifugal force, causing them to plow through the air, and slow the machinery down through wind resistance. Springs are commonly used as the counterforce to keep them from swinging out. Upon increasing speed, centrifugal force and a slight offset of the pivot point on the flaps will overcome the spring tension and cause them to swing out. Once the speed decreases, they return to their inwardmost position. They are usually keyed together so as to operate in unison. Wincharger of Sioux City, Iowa utilized this principle with their wind generators in the early 1930's. The advantages were two-fold: The governer controlled overspeed, hence preventing destruction in high winds and overcurrent in the shunt-wound DC generator; and allowed Wincharger to utilize a two-blade propellor, improving efficiency over the conventional three-blade design. The airbrake was so designed that it would create a dynamic load opposite the propellor, thereby preventing vibration during yaw moments. Design considerations include minimal aerodynamic drag of the airbrake structure and minimizing wear at the pivot points. The most recent manufacture of these was observed on a TV series called "How It's Made." I believe a Canadian firm was shown selling a small wind turbine with what appeared to be a modern copy of Wincharger's method. The flaps may have been fiberglas instead of the original stamped steel or stainless steel that Wincharger used.
     

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