Main Page | See live article | Alphabetical index Windmill near Leiden, Netherlands A windmill is an engine powered by the energy of wind. It often refers to an engine contained in a large building as in traditional post mills, smock mills and tower mills. It also refers to small tower mounted windmills used to pump water on farms and modern wind turbines generating electricity. Table of contents 1 History 1.1 In Europe 1.2 In the United States 2 Links 2.3 Indexes 2.4 mixed 2.5 History 2.6 Theory 2.7 Test and construction History In Europe In Europe, windmills have been used since the Middle Ages and are especially popular in Netherlands. Windmills were developed from the 12th century, apparently from technology gained by crusaders who came into contact with windmills in the Middle East. Persian sources indicate windmill use as early as the 7th century B.C. Common applications of windmills are grain milling, water pumping, threshing, and saw mills. Over the ages, windmills have evolved into more sophisticated and efficient wind-powered water pumps and power generators. In the United States The development of the American type water-pumping windmill was the major factor in allowing the farming of vast areas of North America, which was otherwise devoid of readily accessible water, and also allowed the extension of rail transport systems, throughout the world, into areas where water could be pumped up from underground to supply the needs of the steam locomotives of those early times. They are still used today for the same purpose in some areas of the world where reticulated electricity is not a realistic option (including the American . The many-bladed wind turbine atop a lattice tower made of wood or steel was, for many years, a fixture of the rural landscape throughout rural America. These mills, made by a variety of manufacturers, featured a large number of blades so that they would turn slowly but with considerable torque. A tower-top gearbox converted the rotary motion into reciprocating strokes carried downward through a pole or rod to the wellhead below. In areas not prone to freezing weather, a pump jack (or standard) was mounted at the top of the well below. This was the connection between the windmill and the pump rod, which generally went through the drop pipe to the cylinder below. The pump jack provided a means for manual operation of the pump when the wind was not blowing. Some pump jacks provided a sealed connection, allowing water to be forced out under pressure, but many had a simple spout allowing water to flow away in a trough by gravity. The drop pipe and pump rod continued down deep into the well, terminating at the pump cylinder below the lowest likely water level. A suction tube usually continued a short distance more. This arrangement allowed wells as deep as 400 feet to be constructed, though most were much more shallow. The number of moving parts led to the whole arrangement to be rather trouble prone, and "well men," as they were called in the early days, had a profitable business in repair and maintenance work. The wind turbines and related equipment are still manufactured and installed today in remote parts of the western United States where electric power is not readily available. The arrival of electricity in rural areas, brought by the REA in the 1930s through 1950s, made these windmills obsolete in the Midwest and other more built-up areas. The mills and towers remained for a time. Today, most are gone, victims of storms, rust, and progress. See also: List of windmills watermill windpump wind generator Links Indexes Google: Wind, Windmills, Business: Wind mixed Windmills at Windmill World Paul Gipe has worked with wind energy since 1976. His experience with the technology runs the gamut from measuring wind resources to installing residential wind turbines DTU: Danish wind turbine manufacturers windmission, Windmission: books 2/98 Power from the sky Search for: "Power from the sky". History Google: Mills windmillworld: history Theory wind A Wind Turbine for pumping water Test and construction Paul Gipe: Testing the Power Curves of Small Wind Turbines Building the brakedrum permanent magnet alternator as originally designed by Hugh Piggott Hugh Piggott - Scoraig Wind Electric, Small wind systems for battery charging Article: C. John Dakin, ss. 56-58, Elektor Electronics, 1996.'' "A low-cost wind generator driven battery charger (January) 1 ? (Page) 56" Look under the topic: "Power Supplies & Battery Chargers". Power output: 10 mi/h: 1 Watt; 20 mi/h: 6 Watt; 30 mi/h: 21 Watt. Propeller design: Scrapyard Windmill Realities - Building Windmills with Recycled Parts by Hugh Piggott. Published by The Centre for Alternative Technology. Machynlleth, Powys. Wales SY20 9AZ. Telephone: (01654) 702400. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.