Pictured above is what has affectionately been known as the "Bill Mill", Bill being the border collie who graciously agreed to model for the tail. Some folks think it's me, but one can clearly see it's not me. Anyhow, that is as it looked over 4 years ago, when it was first raised July 5, 2004. Click Here to see details of the original project.
A few months after first putting Bill up in the air, there were some noises and some stainless hardware lying about near the bottom of the tower. So that October, 2004, we did take him down to replace that hardware, but no other maintenance was done. For all intensive purposes, Bill has been flying and making power, unattended, for 4 straight years. Abusive treatment admittedly, but Bill is a workin' dog and has been up to the task.
So fast forward 4 years. A 'grumbling' noise has been heard. Upon going up for a closer listen, it appeared the alternator was resting crookedly atop the tower, so it was decided that a maintenance session was in order. We took it down on July 4, one day short of four straight years.
Now do keep in mind, although some work was definitely well past due, this turbine was making over a KW the day before we brought it down. It was still working surprisingly well....
Unfortunately, the camera we use is even older than the wind turbine, and it died after all pictures were taken of the project, but before the pictures could be saved. So, having heard a picture is worth a lot of words, I had to draw pictures. Not easy with paws. Note that anything red designates a significant problem.
I'm Dixie. A Border Collie. A workin' dog. You may know me from my appearances on CNN and The Today Show, devouring a giant pumpkin, or from my stick toting appearance in the New Belgium video. That's all fun and games, of course, but there is real work to be done.
What you see above is what the old yaw bearing/pipe looked like. Of course, the main generator and tail hinge stub would be welded to this piece, but I can't draw that well. Completely worn through at the bottom, behind the blades. And, where it met the top of the tower stub at the front side, it was worn completely through from the inside. The wind has been pushing back on this for 4 years. Never any grease since July 2004.
Our first thought on this was to cut the bottom and tops of the pipe off, and replace them with new pipe. Keep it quick and easy... that was before we removed the machine from the tower....
Here you see my representation of the stub on top of the tower, after the machine was removed. This was originally pipe over pipe over pipe... many layers for strength. It was worn at the top and bottom of the yaw tube significantly. Two of the three layers of steel were worn completely through in places.. the red lines sort of intended to indicate that. And as you can see, much smaller diameter at the top and bottom. No wonder the machine was crooked. I'm surprised it didn't break off or at least bend.
The very top of the tower stub was also very worn. There was a throw out bearing for a clutch up there, and that bearing was still fine... but the back and forth rocking and really messed up where that bearing rested atop the tower stub.
So... Since the tower stub was so messed up, and obviously needed replaced, we figured it best to replace the whole yaw pipe with a larger pipe, and put a larger pipe over the tower stub as well. That meant taking the alternator apart. Which led to other issues.........
Here is what the stator looked like. The red indicating where there were cracks. It still worked, so we just filled the cracks up with super glue in hopes that will keep it working for a while longer.
The bearings and races... both inner and outer were pretty pitted and noisy even spinning on the work bench. Full of pitting as you can see by all the red dots. Not unlikely, since this was one of the old (the last and heaviest of them) Volvo hub windmills... well those bearings were used when we put them in, so that pitting may well have been there long before they were turned into a wind turbine. In any event, it's now got new bearings and races.
Above you see the wire. It was still holding, but very twisted (as seen by the lettering), and was cracked through to copper in places... likely where it rubbed on the now sharp edges of the top of the tower stub. The old wire has been replaced with a new (slightly used) less twisted wire.
Here you see the new system. New larger tower stub (New tower stub is the same size ast the yaw pipe used to be), welded securely over the old one. The sharp edges cut off the old one so as not to cut the new wire. A flat surface welded to top of the stub, and a bronze bushing in place of the old throw out bearing. George signed it with 'by George' with his grinder when finished.
And of course, a new, larger diameter and longer yaw pipe that fits over the new stub. To do this, we just cut the alternator off the old yaw pipe with oxy/acetylene, and welded it to the new one, same with the tail stub. Again, if I could draw better.....
George came up to help weld the new tower stub on during a lightning storm.
Not pictured was an issue with the magnet rotors. The magnets had backed off the rotors, some about 3/8" (9mm ish) out. In putting them back into place, some of the polyester resin (that we no longer use) chipped out. We glued the magnets back into place with JB Weld, and banded them with stainless steel as Dan has been doing lately. Looks nice too.
One note about using JB Weld for that.. it's messy. It's got ferrous particles, and seeks magnetic fields.
Also not pictures was the poor condition of that 4 year old paint work. Poor Bill had lost almost all his paint on one side, and the paint was flaking off everywhere else. So of course, a paint job was in order.
A total of 8 days down for this maintenance. Really not bad considering that basically everything that could be worn out, was worn out. And back in the air, Bill proudly and dutifully herding the wind.
A new table in place where the alternator comes down sure helped... otherwise it's way high in the air, and the rocks are in the wrong place.
A smile for the camera... Cheers.
[editors note] Dixie lives off grid with 300W of PV Solar, and this wind turbine. Her humans run a fairly large stereo, they watch movies, have an electric fridge, the computer is on about half the time plus lights and occasional power tools. So the wind turbine is critical. Fortunately Dixie mostly eats dry kibble so she doesn't care *that much* except that maintaining the wind turbine is her job (she's a working dog). Her famous video disassembling the giant pumpkin is here:Here
RIP Zubbly and thanks for the giant pumpkin seeds!
