We finished DanF's wind turbine on Monday. A recap...
its a single rotor machine with 12 large 1/2" thick 2" tall wedge shaped magnets on a 12" diameter rotor. The stator is wound with 55 windings of #13 wire per coil, there are 9 coils, it's wired in Star, for a cutin speed of 180 rpm. We've mounted Art Randolfs 8' diameter fiberglass reinforced nylon blades to it. We also worked on his top tower section Monday and got that pretty much finished. We were planning to raise it next monday - but the weather was so nice yesterday -and we had some neighbors willing to help, so we tore into the project yesterday morning.
Here John and I are putting the top of the tower on while Rich bolts it from the bottom. The base of the tower is in concrete, and the plan is to bracket it to his top rafters with a bit of a rubber cusion to dampen some vibration. This is probably not advisable for most folks... DanF thinks he can live with the noise though. His dog didn't get any say in the matter.
Here John and I are hoisting the alternator onto the tower stub. Kind of scary - Im glad (so far) that this is only a single rotor machine. As it is, it weighs about 40 pounds.
We're tightening down the blade set while Rich brings the tail up on the roof.
Once it was all balanced and assembled, we have a rope/pully setup that allows us to raise the machine about 6' above the top of the lattice tower. So there it is all hoisted up ready to go (hopefully!).
There was almost 0 wind yesterday (and this morning) so we didn't get a very good show. It did spin most of the time though in seemingly still air and every now and then we'd have a small 'gust' (perhaps 5- 10 mph.. hard to say) and it would take off. It's very free spinning and starts turning very easily - it speeds up very quickly with only 1 rotor on it. The cogging/drag caused by the magnet rotor facing the stator brackets is a none-issue evidently. We saw lots of 1-3 amps from it (12 - 36 watts) and occasional 8 - 10 amps. But it was a very still afternoon. The blades are fairly quiet so far and it all looks good... so far.
Of course, any time after we raise a wind turbine we have a nice break and get sore necks looking up at it for an hour or two! From left to right in the picture above we have... my vacant chair ('cause Im behind the camera), Captain Augustus Crook (The black and white dog), DanF, Rich (he works with us at the magnet shop), and Kodi (DanF's dog). As usual - lots of fun, I'm dying to see some real wind on this thing/see if the stator melts! I kind of think it'll be OK. It furls early, and it seem fairly well behaved yesterday although we didnt have much wind to watch it in. It did not seem to be stalling, or overspeeding - but we'll know more when we have some breeze.