We had a fun weekend up here working on various RE projects.
The folks who put on the Sustainable Living Fair in Ft Collins asked us if we'd build a wind turbine there this year. Last year we had a booth and brought one of the homebrew machines that we made last summer, it was lots of fun. So, over the course of two days were going to carve blades... wind coils.. etc, it should be fun. DanF made a fun pageabout our experience there last year.My old coil winder is pretty worn (it was only made for 1 machine and I think it's made over 10...) so I made a new one that wobbles a bit less and is a bit easier to use on Sunday.
I also saw fit to make a new mould. My old one is very filthy - a little warped... and it was really designed to work with 11" diameter rotors. Now I'm starting to find nice 12" diameter rotors in the volvo shop dumpster! So my old mould was 14" diameter, this one is 15".
2 weeks ago we had about 3" of rain in about an hour and a half. Since then its rained almost every day....
So the creeks rose! And Scotts hydro plant has spent about 2 full weeks under water. It'd be down the creek, except for the rope he'd thoughtfully attached to it which was tied off to a tree. The picture doesnt show very well... but the magnets in the alternator collected gobs of magnetite sand so it was locked up. He brought that up yesterday and cleaned it off - cleaned the bearing and re-greased it. Now we're definitely going to get 'round to putting a cover over the alternator to keep the water out. Till the flood... it was fine though, and it ran for a couple months with no problems producing a constant 25 watts.. 24/7. We've experimented with 2 different runners, and 3 different nozzels - pointed at it all different ways - and made adjustments to the airgap each time. No matter what we do.. this thing produces about 2 amps. If we get around to it before winter, we'll try some of Nando's suggestions regarding a new runner and nozzel. As it is now though... it's working pretty well and kept Scotts lights on at night over this very cloudy, rainy summer we've had.
I dont have pictures of this yet... but another fun project down at Scotts. His Rooster Wind Turbine was upgraded last week. As it was, we had a 10' diameter prop on it, and it sat on a 30 tower, on the side of a steep hill... in perhaps the most turbulant site I've ever seen up here. He was pretty close to his batteries, and the line was of nice thick wire.... and it had significant stall problems. The alternator was much too powerful for the 10' blade set - at 200 rpm the alternator was wanting to produce about 180 watts. We improved this shortly after raising it, by opening the airgap a bit. He was still not satisfied, and went for the other fix... a bigger prop, and a taller tower. So now she sits at 50' and sports a somewhat wider 11' diameter prop. We've not seen much wind on it yet, but it seems to be doing much better.
Our freind Dennis is building a 14' machine, like the ones on this page. In the picture above he's mounting the tail.
Dennis also finished his stator, and got the alternator together yesterday. He's got a 24 volt system.. this has a cutin speed right at 75 rpm.
Since many of the 10' machines we've been making seem to stall the blades - and using the old 2" diameter X 1/2" thick disks seems to make for an alternator capable of too much power at too low a speed for a 10' blade, I'm trying these smaller magnets on Tims wind turbine. These are the less expensive 1" x 2" x 1/2" thick blocks - I think it will improve the 10' wind turbines. Above is our neighbor Tim's wind turbine coming together. On this one, we only cast the resin around the magnets about 1/4" thick, thinking that this might improve airflow around the stator for better cooling.
Yesterday Tim came down and tried out the new coil winder. Tim's got a 12 volt system, these coils are wound from 2 strands of #14 magnet wire, which is equiv. to #11. There are 34 windings per coil. I tried winding a couple coils with #11 wire, it's too stiff - I couldnt get it to wrap neatly. 2 strands of #14 is much easier to handle.
We did Tims a bit differently than usual. We only wired one phase at a time... we'd lay 3 in the mould, make the connections - take them out, and then solder the connections. Then, when all 3 phases were done, we layed them back in the mould and cast the stator. It was surprisingly easy this way.
Pictured above is Tims stator which came out very nicely. You can see the lines (two black circles) around the holes in the coils... the resin lifted these lines out of the mould, they are the guidelines for where to place the coils, they are the exact path of the magnets. Tims machine should be done real soon, it'll be fun to raise it! We don't need to make a prop for this one, Scott gave Tim his old 10' prop since he replaced it with a larger one. Lots of fun anyhow... we might not be on the cutting edge of new alternator or wind turbine design here, but we're defititely having fun, improving some of the processes a bit and making some power!
