Building the Frame

So the first step is to build the frame of the wind turbine. This is the part that mounts on the tower and holds the entire turbine together. It is a bit more complex then you might first think because there are three separate parts that pivot or spin: the tail pivot, yaw bearing, and the trailer spindle. In the picture below you can see the tail bearing on the left side, the yaw bearing is vertically oriented in the middle, and the trailer spindle on the right side of picture below.
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The primary job of the frame is to orient the entire turbine into the wind so the central shaft, called a yaw bearing, is able to rotate 360 degrees. The yaw bearing will be able to rotate because it slips over a greased bushing on the top of the tower. The tail will hang off the back and swings up and in towards the frame in higher winds. Like the yaw bearing the tail bearing is simply a greased bushing, allowing it to pivot in the wind. Finally, the trailer spindle is where the alternator and blades will be attached via a trailer hub. This all may not make a lot of sense at first, but will become clear a bit later.
All the parts that make up the alternator (copper windings, magnet rotors) and the blades will sit around the spindle. The magnet rotors and blades do the spinning because they are mounted to a 2000 lb trailer hub, which is attached to the spindle on the frame. The stator in this design is stationary and sandwiched between the 2 magnet rotors. So unlike most common AC motor or alternators, the magnets spin, not the copper winding. But, I will cover this all later in other entries.
The design requires you to weld the frame together from a bunch of flat 1/4 inch pieces of steel and schedule 40 pipe. The book outlines exactly what you need to buy and how to measure and cut each piece. You start out with basically all of the parts you see below. I found a couple shops that will cut out the 1/4″ flat parts on either a plasma cutter or water jet cutter for a fairly good price, but I had the otherpower.com guys do it because it they had the best price (and I would rather give them my money anyway).
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And after a bit of work with a plasma cutter and a mig welder you end up with the finished frame below. I used the plasma cutter to cope the ends of the pipes so they fit together.
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I built the wood jig below to set up all the pipes together at exactly the right angles, so I could easily weld the entire frame together without holding things in place. The pipes sit at strange angles so this is really necessary. The spindle points up about 7 degrees and forward a bit, so this orients everything just right.
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Anyway it turned out pretty good and just needs a bit of clean up grinding. I plan on either painting the frame with a marine grade paint to perhaps paying someone to do an electric powder coat. I have to look at prices and see if the powder coat is affordable or not. So, next I am going to build the tail. It should go pretty quickly and then I will have all the welding done.

Homebrew Wind Power

Homebrew Wind Power, by Dan Bartmann and Dan Fink, is really the best book I have found for wind turbine building. Actually, it’s one of only two books I have found on the subject. The other is How To Build a Wind Turbine, by Hugh Piggott. While this is a great book as well, it doesn’t go into as much detail and the tubine design it promotes is not as elegant and simple for an individual to build in a small shop. There are a lot of other articles , how-tos, and websites out there on the subject as well, but these are the only two complete sources, and it is obvious that these guys have spent years perfecting their plans.
The majority of the Homebrew Wind Power book explains how to build the 10 foot diameter horizontal axis wind turbine that I am building. Below you can see a picture of the one I helped build at the Sustainable Living Festival last year. They rate this turbine design at somewhere between 700 and 1000 watts, which is comparable to any commercial wind turbine of the same size. I think they rate this turbine at 1000 watts at high winds like 20 miles per hour. This mean it realistically will generate about 100 kwh a month at a site with an average of only 10 miles per hour winds. For reference, the average household in the US uses 750 kwh a month. So this is pretty significant amount of energy, especially if you are below average in your energy usage.
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They split the task of building this turbine into a bunch of chapters that you can follow step by step: Frame, Tail, Magnet Rotors, Stator, Rectifier, Alternator Assembly, Blades, Rotor Assembly, and Tower. These guys are really good at explaining everything you need to know about each step in the process, even if you have very little experience with this sort of thing. They designed this turbine specifically to be build by non-technical people and with freely available raw materials. The most complex parts of this entire project involve welding and casting parts in polyester (polyester, vinyl and/or epoxy) resin.
Anyway, I will start blogging about the steps I have completed in the next journal entry.

Getting Started

Ok, so I am finally starting a blog in order to document my homebrew wind turbine project. I have been working on this project for a couple months now…off and on, but am finally starting to document it. So here I am getting started. At this point I have made some progress and have some good pictures, so I think it is a good time to get started.
Anyway, I am building a 10 foot diameter horizontal axis wind turbine. I have been interested in alternative energy for many years ago and first started thinking about building homebrew wind turbines when I stumbled upon the www.otherpower.com website. These guys are really interesting. They all live off the grid outside of Fort Collins and they generate all their own power by building homebrew wind turbines from scratch. I mean really from scratch…they weld the frame, wind the copper, cast the stator in resin, etc. It is pretty damn amazing. They have become so good at it that they teach people in seminars all over the country. I first ran into them at the sustainable living festival in 2007. I found out that they give 2 day workshops at the fair, so I signed up for both days in 2008.
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So we built two wind turbines with these guys over 2 days and I couldn’t believe how quickly we put these things together. I realized that they really had put an incredible amount of time and thought into designing a very efficient, reliable, and affordable wind turbine that could be built by just about anyone. I was really impressed and knew at that point that I had to try to build one myself, in my own shop. So, I got started right away and manage to find a few hours here and there, between work and family life to work on it. The otherpower guys even published a book called “Homewbrew Wind Power” and this is what I am using primarily as my guide.
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I started by buying most of the raw materials that you need to build two 10 foot wind turbines. Amazingly, it only cost roughly $600 dollars for the materials, with the steel parts, neodymium magnets, and copper being the primary expenses. This cost of steel and copper is pretty high so I imagine the you could have build one of these for far less just a few years ago. This is still incredibly cheap though for a wind turbine. Of course, this doesn’t include the cost of your time. It looks like a comparable commercial wind turbine of this size and rating would cost at least $5,000 dollars. This is pretty impressive really.
Anyway, this is enough for tonight. I ‘ll start getting into some of the wind turbine specifications and building details in the next entry. If you don’t like technical stuff and geeking out over tools, welding, physics, etc. you may want to stop reading this blog 🙂