It's been a busy summer and I've not got around to posting much stuff here. We've been building lots of machines, installing a couple, finishing the book project and teaching a couple work shops. Our most exciting workshop was perhaps last week, we had 8 folks from around the country/world here for a 5 day work shop, they all camped up here and stayed with us for the week. The 'goal' of this workshop was to build a 12 foot diameter wind turbine from scratch, then build a 64 foot tower and install the machine. There were a few days preparation before the work shop, we wanted a head start on the tower. The ground is pretty flat, and we decided to build without any concrete. The anchors are 'dead men' buried 4' under the ground. Pictured above is the dead man for the back anchor, with a shelf where we'll bolt the winch.
We used 12 gage 6 inch diameter tubing for the tower. Pictured above are 5 20 foot sections, 3 for the tower, one and a half the for the gin pole, and the extra 10 feet for couplers.
The rest of the tower anchors are dead men as pictured above - pipe, welded to flat steel welded to old tire rims w/tires on them.
We used Bob's 'tinkertoy' for all the excavation.
Folks showed up last Sunday for the workshop and we got right down to work on Monday the 12th. We talked theory for the first few hours and started building. This 12' turbine is very similar to the one we made at the last workshop in Wisconsin, and the one we made for Blue Energy. It's got 14inch steel rotors (which we torch cut), each with 16 N42 grade disk magnets, 2 inch diameter x 1/2" thick. The coils are wound with 2 strands of 13 gage wire and 35 turns per coil. Pictured above Rich is teaching folks to build the stator.
Scotty helped with blades for the first two days of the work shop. Pictured above he's got Tyler (he flew out here from Guam) tapering the thickness of the blades on the band saw.
The power planer is loud/messy so we setup a workbench outside for that work.
The goal was for the first 3 days, to finish the wind turbine and all the tower parts. Pictured above are the couplers for the tower and the gin pole.
Phil came here with lots of metal work experience. Pictured above he's welding the stator bracket together for the 12 foot wind turbine, it's built from 2.5inch x 3/8 inch bar stock.
By the end of the first day the fronts were finished on all the blades.
Thank you Brian from sustainablelivingfair.org for bringing along a 40 cup coffee maker and lots of good coffee to keep us going!
The stator bracket welded to the spindle. This machine uses a #42 spindle. The hub/spindle is rated for a 6000 pound trailer axle. It should hopefully be fairly bomb proof - it's the same setup I used for the 20 foot wind turbine and this one is a fraction of the weight/swept area. The rest of the frame the same size as my old 17 foot wind turbine.
Pictured above Phil (from Texas) is measuring pipe for the yaw bearing while George stands on a chair.
We gathered everyone up so George could give a good talk on the cutting torch, how to use it, and safety issues. Then folks practiced.
Rich had the stator cast by about noon on the second day.
Trang with the cutting torch!
A big thanks to our good friend/neighbor Lynn for providing a gourmet dinner for everyone at 6:00 sharp every night!
There were a couple oversights with this machine (since we've only built one just exactly like it before). The hole in the stator was too small for hub, so Ron had to put up with my worn out, 115 year old Flather metal lathe and turn it down. Also - I have always liked to put a rotor behind the hub, and one in front. I have always taken for granted the idea that the back machined surface of the hub should be true with the front! This is the 2nd time (out of about 10) that it wasn't, and we had to turn the back of the hub down.
There's the 12 foot turbine with the back magnet rotor on. The stator is 17 inches square, 1/2 inch thick. The yaw bearing is made from 4 inch pipe, 2 feet long. The tail pivot is 2 inch pipe over which the tail bearing (made from 2.5 inch pipe) fits.
Pictured above George helps Ron fit the tail to the tail boom.
Our goal was a cutin speed (25 Volts DC) of 125 rpm. We ran the output through a 3 phase rectifier and used a laser tach to test it. It came out 25VDC @ 126.2 rpm! Not bad....
I got a nice 2000 pound Thern Winch off ebay for $60 for the tower. We did the math and it came out such that about 7 foot pounds of torque on the shaft should raise the tower - so, we figured a cordless drill would be up to the job. The winch has a 5/8 inch shaft, Phil had to make an adaptor so it would fit in a half inch chuck.
By Wednesday afternoon they were just getting the blades together. They came out really nice.
At the end of the day Wednesday we had the machine completely finished and tested. It came out nicely. Lots of pictures here so I'll continue this in a second posting - the next one will be about the tower.
