I think your moderate idea would work, and as an experiment would be fine. Maybe FeralAir can chime in about his current experience with hanging the rotor from the top. I'm in the process of putting a S type together that'll be heavy. I scrounged a clutch throw-out bearing from a Porsche 930 for the rig to sit atop and not transfer any compression loads onto the outputshaft. I think these things need solid top and bottom support to be safe and stable.
Height- the higher the better- just like hawt, it wants clean air.
Think low speed with Savonius. Your gen will either need to be able to produce at low rpm, or gearing will need to be implemented to get the alt speed up. I think Ghurd suggested a stepper motor for small units.
Fiddle-on, dude.
David
There's even a design for a mini single rotor air core axial alternator. http://www.instructables.com/id/Pringles-Wind-Turbine-Pleech---Version-One/?ALLSTEPS
There is also a more robust version on the same site - Instructables (it's a bit childish, I love it) http://www.instructables.com/id/Build-a-Savonius-Wind-Turbine-or-VAWT-to-make-elec/?ALLSTEPS
Have fun.
Ben.
I am playing with McDonald's soda cups now. :-) Same idea. G-[ Parent ]
No, at the moment I'm just trying to make something mechanically workable.
Then I'll probably cheat and try to buy a motor/gen...
My tweaking is coming along, and I may even have something that I can put in the garden to spin by itself tomorrow... What I believe TomW may call "yard art" but in this case becomes "educational toy"!
Rgds
Damon[ Parent ]
I won't put any more time or money into a small VAWT. A 40cm diameter HAWT is cheaper, easier, and I got at least measurable power. I certainly wouldn't bother building it dual-rotor PMA!
It is probably best suited to an 8V stepper motor for LEDs or AA nicd/nimh. Meaning TomW's 'yard art' or a useful "educational toy". Don't be offended. TomW is a realist looking from the perspective of powering a household instead of powering a digital camera.
It will be big fun. It could be usable, in a small sort of way. It won't cost much (with a stepper motor). Build a similar HAWT, be it similar in cost or swept area or whatever. It will show why nobody has a proven commercial 50+W VAWT. Ed might do it, but that is a completely different animal.
To summarize, slap a stepper on it and be happy. :-) G- [ Parent ]
.....Bill [ Parent ]
The 0.3m swept area one that I was looking at was ~$9k from the US distributor.
I'm waiting for pricing from the UK distributor.
Next thing I'll be asking you where to get the magnets in the UK! B^>
Hanging it like that doesn't really work unfortunately. When I hung my pb-vawt from a (crude) u-joint the swinging motion took up a lot of the wind's power and it looked like it was slowing the rotation every time it swung back. It's now got top and bottom bearings and spins much faster/nicer.
I think a good-sized weight at the bottom would help a little if the weight wasn't being spun. You might be able to use a couple of magnets as bearings for that part.
If you plan to trying this out on a larger scale and more permanently then consider the stress on the bearings over time. Maybe bike wheel hubs would last a few years...that's what I'm using on my big one and I'm crossing my fingers.
If you go with gearing I think 1:10 is about right. When I hooked a radiator fan motor to my pb-vawt the ratio was 1:5 and I got a tickle-on-the-tongue for output - not quite the bite of a 9v battery. The vawt was spinning around 36rpm or so, so the motor would've only been spinning around 180rpm...
With a 1:10 ratio, when your vawt hits 100rpm the motor will spin at 1000rpm. That seems decent. If it's smaller and faster then maybe 1:8...I dunno, it's variable and needs to be done on a case-by-case basis, I think.
This came out longer than I thought it would...I'm just glad I'm not the only one with the bug![ Parent ]
