These wind turbines are Hugh Piggott design and we built them from his 'Wind Turbine recipe book'. see https://scoraigwind.co.uk/all-of-the-books-by-hugh-how-to-get-them/
They are 3.7m, 12 footers, and two of them have our especially made fiberglass blades from our own moulds, and these 3 have been flying for nearly 12 years.
We have wound the 3 phase coils for DC battery charging at between 46v and 61v and are directly clamped/connected to the 48v battery. Any excess electricity is diverted by controllers to dump load heaters. .
The design of the blade and the PMG permanent magnet generator, are very well matched together for optimal output. The tail design has the ability to pull the wind turbine out of the wind direction if the wind increases to dangerous and excessive levels.
My Wind Turbine No2, 3.7m dia, (12 footer) gets a REBUILD.
Early this year, 2021, my No2, been up 11 years, suffered a total failure, as the so called 18mm thick marine plywood that clamps both sides of the blades just turned to cardboard. Obviously the Marine Plywood was not Marine Ply.
And the blades just flew apart. These blades were a fiberglass design and about 3 times the weight of normal cedar wood blades.
The photo below shows one blade with a bit of one of the hubs of the so called Marine ply, the other photo shows the damage to the Permanent Magnet Generator, PMG...
These blades as they flew apart then bent the main 12mm stainless steel bolts and damaged 3 of the cast resin coil Stator mounts.
So re-cast the 12 coil stator using Epoxy resin over the reduced size
and repaired polyester cast by grinding out the cracks and fractures to the original polyester casting.
Also did the same to the 2 magnet discs.
After 14 years of use in outside conditions, Polyester is waterproof but not UV stable as is polyurethane varnish. Viynlester, is used as a gel coat, but its not waterproof but UV stable. Epoxy, is so far in my limited use, waterproof and UV stable.
New BLADES.
To be 3off for a 3.7m diameter Wind turbine. TSR about 7, (tip speed ratio), using Hugh Piggots wonderful designs for his 3.6m diameter.
These new blades for No 2 wind turbine will be made from Red Cedar, and not our Fiberglass design, why? well the fiberglass materials and all the required resins and the mess involved, are now more expensive and more time consuming just making 3off . And i now have a good supply of Red cedar wood.
My good friend 'Dimitri', French 'Off Grid' Log Cabin Nut, his profession is a forester with all the machines to cut and drag out, had these red cedar collected from a nearby council who had put them aside for burning from there ornamental tree arboretum so no cost to Dimitri. He cut them up into usable logs, and i bagged a good section with minimal knots and a good straight grain.
6 years later and seasoned we cut the section up for 6off Wind Turbine blanks all quarter sawn and reasonable straight grain.
