My oversized savonius

[rfirth]

Hey! I've always wanted to build a wind turbine and I finally decided to just do it. I couldn't make the tower tall, and I didn't want it to spin too fast, so I built a rather large savonius wind turbine.

The rotor itself is made of two pieces, offset by 90 degress. Each of those pieces is 6 feet wide, 3 feet tall, and 2 feet deep. It resembles a giant flying coffee table, if you could imagine such a thing. The whole thing sits on a frame about 5 feet off the ground, and the top of the entire structure extends up 12 feet. It is constructed of wood, with cloth streched over the frame of the rotor. It uses about 90% used wood from a Habitat for Humanity ReStore, and cost about $150 to construct.

Here's a picture with me in front of it (warning, about 990kb):

http://winvistainfo.org/Documents/DSCF1763.jpg

Since then we've added flowers as decorations:

http://members.cox.net/nanee123/wind_turbine.jpg

Also, I have 2 videos of it in use, first in low winds, second video in faster winds of about 20mph I think:

http://www.youtube.com/watch?v=XMv2CEGXwqU

http://www.youtube.com/watch?v=M-aZWt6iFyc

Anyway, it's cool. It turns in winds almost too light to be felt. Not that there is much useable power in winds that light. We've also had people park their cars in the street to come talk to us. The neighbors all like it, but I'm not so sure the homeowners' association will. I'll be waiting a long time before adding a generator because of that.

So, the whole thing has a sweep area of about 3.3 square meters. I'm hoping for 500 watts at in a 30 mph wind. I was looking at buying 24 of those N42 2x1x0.5 inch rare earth magnets and some magnet wire to make an alternator. For a 3 phase alternator with 24 magnets, I'd need 18 coils, right? I have to keep in mind that this is a pretty low rpm machine, and hardly ever does more than 20-30 rpm except on a few wind days, or in a thunderstorm. I was also looking at using gearing. Of course that will make my efficiency even lower, but it might help with my very low rpms.

My question is - what gauge wire, and how many turns? I'm aiming for 12 volts in winds under 100 mph.

I'm sure by time I'm done, a solar pannel would have been cheaper and provide more power, but where is the fun in that?

[JW]

Alright Rfirth,

 First off, Welcome to the board/forum... This is the first time ive seen you, so if youve been around a while, oh well but youre on the frontpage, so i guess inquiring minds want to know

 "My question is - what gauge wire, and how many turns? I'm aiming for 12 volts in winds under 100 mph.-rfirth"

 Hmmmmmm,

 Thats kind of vauge as far as questions go around here, for example the 'amp hour capacity' of your batt bank would be helpful.

 Also, what is the average wind speed, that you intend to hit your VAWT?

 What are your intended loads? do you intend to have more than one mill in operation at any given time?

 Have you considered a diversion load?

 Is your design intending to negate such a factor, such as a diversion load, by 100% matching of the load.

 Have you considered the mercedies benz limit

Seriously though, Im just trying to get more information available about your system, to make it easier for the group to help. Your post contains many words that would lead to successful search criteria 'of this board' not a google search, also, consider this(a search of the board), as you get some replies, it will help to see what others have done, enable you to sidestep re-inventing the wheel so to speak.

Best

JW

 

[rfirth]

Thanks! Yes, this is my first time posting, but I've been reading this forum for a few years now. We just moved to an area with a much better wind resource than the area we lived before, and I jumped on the opportunity.

I think the average wind speed here is about 12 mph. During the day it is often more windy than that, but at night it usually goes almost completely calm. We also often have strong thunderstorms that bring high winds.

This is very likely to be the only mill to ever be installed on the property. I don't have any batteries yet, and I was considering just using a grid-tie inverter. It seems I read somewhere here that batteries should be used with wind applications because most inverters are built for solar, or some such.

I'm not 100% sure what you mean by a diversion load. Do you mean some kind of load for when the batteries are full to prevent over charging? Or do you mean to keep the mill from over-speeding in high winds?

Even if it is never hooked up to a generator, it gets people thinking about alternative energy. It looks cool, and we've had no shortage of people slowing down to take a look.

Anyway, I'd probably be able to answer your questions better in the morning. It's about 1AM now and I'm tired

[agin]

I am new at this and just trying to learn, so I can not help with your question. I do think I can help with one of your concerns. There are a lot of laws being considered and passed to stop HOAs from restricting your rights to become less energy dependent. A lot of HOAs used to say no sat dishes, federal law says differently. You have rights, it just takes a while for some HOAs to realize that.