Brian's Morning Newsletter March 25th 2008
Good morning
Well I've been busy since I woke at 5:00 AM, now it is almost 7:30 and I didn't even notice. Anyway I've gotten a fair amount accomplished during my time online this morning. Synergy Fest is one month away and our wind turbine project isn't moving along like I hoped. After wasting more than enough time being disappointed in the community college's ability to support this project, I decided to use some of the money I have saved for the renewable energy workshop to buy supplies for building our own wind turbines. One aspect of building these machines I find most interesting is the vinyl ester resin casting of the stators. Inside the plastic of the stator are the copper windings. After we build the rotors with permanent magnets arranged in a similar pattern as the windings, we are closer to having the axial flux alternator portion of our wind turbines ready.
I guess I should explain this a little bit better. The dual rotor assemblies rotate on an axle & hub assembly which I purchased from a company called E-Trailer. I bought three axle & hub assemblies for Kevin's, Louie's and our wind turbine. I also bought one gallon of vinyl ester resin and ATH - Alumina Trihydrate powder to be used as structural filler in the resin and four yards of fiber glass cloth for building the stators. I hope Kevin has enough copper wire for three axial flux wind turbines. It looks like Louie is making good progress building the blades. Anyway the rotors spin around the stator which as the name implies is stationary and sandwiched between the rotors. This is the homemade alternator. We still need steel. Holy cow, steel is getting more expensive by the day. We got one quote that put most raw steel over hundred bucks per piece, and that's just the normal pipe, when we asked for prices for the 6 inch thin wall steel tube for the tower we got numbers in the $500 per twenty foot length range.
One reader sent us an alternative to expensive single pipe tower material. Thank you Weldon. These structures are a geodesic design, and according to Weldon easily constructed from standard steel electrical conduit obtained from a hardware store. Plus, these towers are pretty cool looking. Reminds me of the geodesic dome we used as a green house when I lived at my brother's artist commune back in California in the, dare I say, "60's." We need to build a tower for the first wind turbine we built in Colorado. We already have the alternator and blades ready to go. My plan is to use steel I have here at the ranch to construct the tower for the system we will display at Synergy Fest on the 25th of April. Dang, that date is headed this way fast. I am getting seriously anxious, which of course is why I'm writing all about it. Besides letting off steam with this newsletter, I am happy to say I got a few more pieces of the puzzle put together too, so I feel better all ready.
The hard part of building anything for the fist time is of course not having experience to fall back on. Building wind turbines add a half dozen aspects to what I personally know nothing about. Nothing like stepping into the unknown to keep one on his toes. We have to build the tower. Well all right, I built the wireless Internet relay tower that is up on the ridge, but it is one section of twenty foot steel square tubing. The wind turbine needs to be way up there. Pretty much as high as we can get it. I drove by the park where Synergy Fest is held and to me without any equipment to gauge height, guess the trees are forty five feet tall. The wind turbine needs to be thirty feet away from obstructions, whether above or just beyond. This means that if we can get the tower far enough away from the trees it can be just above them. My goal is to build a fifty foot tower. More than twice as tall as my WiFi tower. Yikes. What have I gotten myself into?
Currently, as far as I can figure, we still need the power cable to run from the top of the tower to the batteries, guy cable long enough to run from near the top to the ground four times plus the angle, I think the rule is the cable is anchored half the distance away from the tower at the base as the tower is tall. Pythagorean theorem: 
or 
The square on the hypotenuse is equal to the sum of the squares on the other two sides. In our case, the height is fifty feet, so square this 2500, add it to the bottom of 25 feet squared 625 and get the square root of 3125 which is 55.9 feet that each of the four cables must be and a 200 foot roll isn't going to make it. This is just the top cables. We also need a set of four in the middle as well, although the lower cable can be smaller gauge. Hmmm. So you can see that my brain is pretty well occupied with the multitude of associated aspects of building our first wind turbine. There just isn't much room for any other thinking.
