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Vertical Wind Turbine Generator Blades
Buy a set of wind turbine generator blades for a VAWT
If you are interested in making your own vertical axis wind turbine (1) (VAWT) generator, then you should take a look on eBay UK. surmise81 (2) is selling blade sets which can be fitted onto a suitable permanent magnet generator (3) or stepper motor (4) to make a Savonius (5) type wind turbine generator.
These VAWT blades are made from lightweight aluminium with a 1.000" diameter hub. The hub can be connected to a generator by screwing it directly to the generator shaft (you'll need to have at least basic metalwork skills and tools), or using a pulley or chain of some sort.
The blades have been selling well for the last few weeks with prices reaching up to £40 plus £6.50 for UK postage.
How Much Power Can These VAWT Blades Generate
The VAWT blade set has blades with a height of 29cm and an outside diameter of around 40.5cm. This gives a swept area of 0.12 square metres. The amount of power in the wind is given by:0.5 * air density * swept area * cube of the wind speed
* find out more about this wind power calculation (6) here.
Therefore, in a 5 m/s wind (average wind speed in a pretty good location), there is 0.5 * 1.23 (at sea level) * 0.12 * (5x5x5) = 9 Watts of wind energy hitting the blades, and 10 m/s wind, 74 Watts.
Not all of that wind power can be converted into electrical power because of the Betz limit (7) and inefficiencies in the generator and bearings - so we shall assume that one-third of that power can be taken from the wind and turned into electricity. Hence a wind turbine generator made with these VAWT blades will generate no more than 3 Watts of electricity in a 5 m/s (11mph) wind, and 25 Watts in a 10 m/s (22mph) wind.
Web Link References
(1) http://www.reuk.co.uk/VAWT-Vertical-Axis-Wind-Turbine.htm(2) http://search.ebay.co.uk/_W0QQsassZsurmise81QQhtZ-1
(3) http://www.reuk.co.uk/Permanent-Magnet-Generator.htm
(4) http://www.reuk.co.uk/Electricity-with-Stepper-Motors.htm
(5) http://www.reuk.co.uk/Savonius-Wind-Turbines.htm
(6) http://www.reuk.co.uk/Calculation-of-Wind-Power.htm
(7) http://www.reuk.co.uk/Betz-Limit.htm
Article from REUK.co.uk:
http://www.reuk.co.uk/Vertical-Wind-Turbine-Generator-Blades.htm
Published: 30th January 2007
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