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This page is somewhat of a diary about the construction of wind turbines we built throughout the winter of 2004. These machines are nearly identical to 10' wind turbines we built last summer, so most of the construction details are the same. So, this page will not go into much detail, Click here for the more detailed information on how these are made. In building these however, there were some improvements made and lots of fun had. This diary will document most of that! All of these wind turbines are 10' machines, we call it the 'Wind Farm'... because all these machines had animal tails! Again, it's a diary of upgrades and fun times had, there is no specific order of events, just lots of fun pictures and captions.
There are a few favorite ways to make blades, and in my opinion how we do it has a lot to do with the nature of the wood. I prefer to rough them out with a drawknif and finish with a power planer and sander. In this case, we have very nice knotless, tight grained fir. The drawknife seemed very tedious near the root of the blade. Usually when this is the case we'd cut slots with a handsaw and remove the wood with a hammer and chizel. Here we found a nice shortcut using a sawzall! This is our good freind Adam who attendended Hugh Piggott's Wind Turbine Seminar up on Guemes Island in 2003 with us.
Our freind and neighbor Scott came up to build a machine, he decided to go with the rooster for a tail.
A small improvement to the stator mould. Here we have Scott's stator setting up. For the lid of the mould we used a 14" diameter steel disk and bolted it down tightly with a 1/2" bolt/nut. This made the stator come out very nice and thin - it was much nicer than using clamps or screws like we have before.
Above is pictured Scott's blade set. We carved these from standard 2X10 lumber from a lumber yard... about $25 worth of wood. Lots cheaper than the fir, we had to settle for a few small knots but nothing too bad.
Here Scott is assembling the plywood hub that holds the blades together with 1.5" long wood screws.
Here the alternator is almost finished. Like all the others, we started with the strut tower from a Volvo 240 sedan. The brake rotors were used as magnet rotors in the alternators. These brake rotors are 11.25" diameter and are from a later model Volvo 850. There is one big change in these machines we've made to the stator. The earlier versions had the stator wired in Delta, and if I recall we had something like 65 windings of #14 gage in each coil. This one is wound from #11 wire, (or two strands of #14 tied together which is equivelant) and we have 35 windings per coil. This raises the cutin speed slightly, although after watching these machines and finding that we need to open the airgap on almost all of them a bit, I think next time Ill lower it to 30 windings or perhaps try running them with a slightly larger prop.
Here we have the tail up on the site where we raised the machine. Beneath it is the tail for his antique Windcharger Giant, which was origionally a 32 volt machine with an 11' prop. His was always missing some parts and he was running a belt off the blades to a PM DC motor which worked out OK, but it had some problems and we replaced it.
Here we are assembling the machine on the tower top.
And there it sits! We had about 4 days into building this machine. It sits on a tower slightly over 30', and not really on the best of sites. It's on a hillside in a very turbulant area... but it works allright. When we first put the machine up it had a problem stalling the blades. We were cutting in just above 120 rpm, and at 180 rpm (which we'd expect in perhaps a 10mph wind) we were seeing about 20 amps output. Since there is nowhere near the power in a 10mph wind to produce 20 amps from a 10' diameter prop, the blades were stalling rather badly. Opening the airgap by about 1/16" helped this, although I think we could go a bit further with it.
Here is another machine our neighbor Adam has built. He's fortunate enough to have a 48 volt system. The coils in this stator are wound from 120 windings of #16 wire. His cutin speed is more reasonable, around 140 rpm, I think he may have fewer problems with stall but time will tell since we have yet to raise this one.
Adams tail is in primer... but it will be a white whale.
Click Here for page 2 all about the pigmill!