Hi All,
I've been playing with Lego again
After seeing some previous successes with the Sandia savonius VAWT ( US Patent 5,494,407 )
I had a go at a similar one in Lego, I went for a blade diameter of 150mm (approx 6"), the height ended up being 176mm.
The diagram is printed to scale (& size I want and the frame is made of axles and axle joiners, a few bushes and some short liftarms.
I covered the main surfaces with paper stuck on with insulation tape, I then covered and strengthened other parts of the blade with aluminium tape.
I live in a flat and when the wind is in the right direction it hits one outside wall, does a 90deg right turn against another wall. When my kitchen window and balcony door are open, the wind rushes in thru the kitchen window... sometimes hard enough to pull papers off the fridge (attached with magnets)
The image above shows a rotor and a coil, initial testing revealed peak rpm to be around 600... wind speed=a huge blast in the face
With a moderate breeze, the turbine was turning nicely at 300-450 rpm and picked up speed quickly with gusts.
The blade starts really easily... mmm...
I grabbed my 3 phase alt and hooked it up with a couple of universal joints and an axle.
The frame has a couple of deflectors to make up for the lack of end plates on the blade.
The turbine coped with turning the alt directly, and got the rotors to 600+rpm. I tried with 3:1 gearing, however, it was only with the strongest gusts that the alt would turn, and then only to a max of well below 200 rpm... (no freq reading
Directly driven and the alt on star output, open voltage peaks around 4.4 volts.
Pleased with the apparent ability of Lego, paper and tape, I tested voltage output and hooked up a 1.2v 1500mA NiCad.
Here the alt is running at 0.02kHz (400 rpm), and is putting 20mA into the cell.
The image below was taken as a big gust hit, 1.45v, 0.12A (0.174W) the ammeter peaked at 0.14A just after.
Another couple of windy days and that cell may be charged
On with the fun )
paul