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Forum Index : Windmills : F&P@PE
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| Dinges Senior Member  Joined: 04/01/2008 Location: AlbaniaPosts: 510 |
Thanks for satisfying my curiosity. Impressive piece of workmanship. I especially like that the generator is sealed from the environment, my main worry with conventional axial flux construction. Should I ever build another axial flux it will be similar to yours (weatherprotection), but of more conventional configuration (3phase, 9/12) Has it been running for 14 years in the outside as a windgenerator then? Impressive piece of reliability engineering in that case. Peter. |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi dinges, Thanks for the kind comments. I had to think about how I would go about this for over a year. I processed most of my ideas in the biological computer, before building a prototype that was adaptable for testing coils and wire and phases and air gaps etc. This concept was originally destined as a solar car engine. I had a fixed battery of 48V, 4x12V PbAcid accumulators. I had made a 2speed gearbox, of 3.3:1 and 1:1 ratios. There was a fixed belt drive to the wheel with a 3.3:1 reduction gearing. This gave a low ratio for hill climbing and one for flat road cruising for a 60kph road speed. The design operating power was 650W to maintain 60kph on level ground. The motor was designed to operate at 3000rpm. This gave a flux transition rate of 550Hz at full speed. This motor had to have the lowest possible losses, as there was a finite power source. The testing had suggested 4phase to give the lowest copper losses and better distribution of losses in the electronic commutator. The magnets were the most powerful I could have made with my budget. These were made in China and had the latest improvements, N34-110deg operating temp and nickel plating, but not much choice of sizes. My test magnets were not plated. You will notice that in my photos, the magnet rotors are dark in colour. The original plating was not very good and peeled off with the encapsulant. I had to remove all plating and re-encapsulating the magnets with resin. The first year I tried to break the motor with load testing on the bench. There was another year about with road testing in the solar car chasis. The solar race was postponed for a year, and unfortunately my solar array was rain damaged and the motor suffered as well. I was unable to replace the array, so the car did not race. The motor spent a many years in an electric bike, as a wheel motor, in a 20" rim, with 24V battery. This was dismantled when the novelty wore off. I moved house and decided that the motor would be good as a windmill to produce electricity where I live now. I sourced some blades[Lakota brand] and had a yaw box and tower made. Much of what has happened since with electronic power maximising has been posted on various links on this forum. The unit was stored for about 3 years in a box. The last 2 and a bit years, it has been a windmill. An indicator of the salt content of the air is that bare copper wiring goes green in a few weeks. Unprotected steel soon shows rusting. Outside surfaces get an oily feel with the salty dust that accumulates. I have given up trying to keep a brass door bell shiny. The weathered look is not that bad. I paid a lot of attention to the weather proofing. No good having a good housing if the bearings don't last and you destroy a stator when a bearing collapses. I have seen many motors damaged beyond repair when poling occurs and the rotor catches the end of a pole finger and cuts the wiring with a resultant bang that makes a hole and copper plates the surrounding area. Not good on a 100kW motor. The most significant point with long service life is heat. If the efficiency is high and there is little temp rise above ambient during operation, then bearing lubricant does not dry out. Keeping the dust and water out should be achieved with non contact sealing, for low friction. All of these components were achieved in my unit. Hi feix62k, I think you get it that I used no plans as such. I would not call it a beast, but a work of art. I started with 10'x4'x0.5" flat plate of tensile grade aluminium that I cut a disc from with a hand jig saw. I then made 5 more the same. All the rings were hand rough cut with jigsaw, including the iron magnet backing rings. It is beyond this thread to explain all the steps, but basically the motor grew as plates were added and then machined etc, etc. The mould to cast the stator was probably the most tricky, as it had to be done without anything to measure against as a reference. I probably should have made the stator first, and then made the rotor to fit around it. Once the magnets were added then another can of worms opened, with modifications to the rotor to allow disassembly, with the making of tensile extracion screws and the matching tensile steel push ends. Aluminium is not strong enough as the push end and the seat would distort and wear away if used. The magnet attracion is very strong as the rotor disks come togeter. The rotor was made with minimal windage from exposed bolts, inside and outside. All the bolts were countersunk to make the spinning rotor less prone to catching foreign objects that may come into contact with it, including air. This alternator was an original idea of mine. The 3blades are Lakota brand[carbon fibre type], the bearings are Koyo 6812z type and the wire was custom made on order by a boutique wire company in USA. The magnets are old tech now and were made in China. This was a big deal at the time. The coils are not just laid side by side like modern axial designs by others, but are overlapping and shaped on a mould to interlock each other. Each coil overlaps 3 others [I would try a slightly different arrangement if I make another]. I made a laminated wooden adapter for the blades, that bolted to my alternator[as seen in the last photo]. The hub is bolted to the face of the yaw box with cap screws. There are no nuts used in any part of the unit, and all bolts have threaded holes in the housing. The alternator is not modified from what I made for my solar car. I have been very pleased with this unit as a windmill. It is certainly better use than just leaving it in storage as a keepsake. Gordon. become more energy aware |
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oztules Guru  Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Gordon, That motor/ alt is a beautiful thing. I could carry on for ages, but that is the nub of it. Damn good idea, done very very well. You certainly seem to have gotten the power density up.... and then some.... Think I'll go and have another drool... 
..........oztules Village idiot...or... just another hack out of his depth |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Nice to see Gordon,, You are an inspiration to so many of us. It's so nice when guys come along and show us what they have done ,.I never miss a post,every one of them tells us something more to think about . Well done ,Gordon. and the rest of the contributors to this site.. plus Glenn for starting this world class forum. Bruce Bushboy |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Oztules, I get really excited each time I open up the AxFx and all is still intact. I am still amazed at how well the stator has stood up to the abuse as a windmill. The magnet rings and the rotor are pretty strong, but the stator is only 2mm thick and there is no glass or other reinforcing in the resin binder. The ridge around the outside edge of the stator, where the straight sections of wire in the coils are connected helps. I am thinking about making a spare. This will have to be a gunna job. [gunna get round to it one day] Hi Bruce, You can see why this was a one off. The AxFx is back in operation. The first day was a bit sluggish with little wind. The bearings were not replaced. I repacked them with my low friction lube combo. It needed a bit more wind to get going at first, but now starts with the lightest puff of wind. I have replaced the bearing spacing packers with teflon now, and this has improved the tollerances, so the shaft and stator alignment is more accurate. I am planning on making some new higher aspect blades to complete the make over. I will be modelling them on the Lakota set I have, but 300mm longer. These will end up approx 2.7m dia. I will make 2 sets, hopefully the same, one set for each mill with a spare. I was looking at composites, but wood is looking most likely now. This will be my next major project. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I have had delevery of a copy machine, so new blades can be my next project. I will be making a new model, fashioned from the shorter lakota blades I have. There will be a bit of hand working on the plug to extend the tip while still maintaining the correct airfoil. I will continue the twist and taper. There will need to be a slight adjustment to the hub fixing point angle, to allow for the new tip angle, to bring it back to 3degrees. This should not affect the overall performance too much. The larger rotor area will more than compensate. I intend to make copies from the new model. I think this will produce more balanced and accurate sets of blades, than ones individually cut and finished. These will be quite light. I am hoping to achieve a finished blade weight of under 1kg with Douglas Fir as the blank. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I think it may be interesting to show some recorded wind data from where my mills are situated. These are on the southern Fleurieu Peninsula, near Victor Harbor in South Australia. I would rate my wind site as OK. There are 4years of data, in some graphs. The data is Wind Run. This is an accumulated amount of the total wind that has passed a point in the timing period measured in kilometers. 
There is some lost data in 2007 when the recording computer died. The logged data is at 10 minute intervals from averages taken from a 1 second update rate. The wind is well proportioned during the year. There is no time without some wind. There is less wind during the winter months, that may seem odd. I recorded the weather data for 12 months before deciding a windmill would be viable for useful power generation and not just an ornament. I would recommend some data collection at the selected wind site prior to building or installing a windmill. I have seen some windmills that are ornaments, that have been paid for with tax payer dollars. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I have been setting up the copy machine, in preparation for making some new blades. It is so long since I looked hard at the Lakota blades. I had forgotten how thin an airfoil section they have. I will be able to make a finished blade from a 55mm thick plank. I will use the same offset, so the new blades, 300mm longer will still mount to the flat rotor surface. I will be making a new plug, that will be very rigid, to help maintain airfoil accuracy. This will reduce the wood that needs to be removed. The front and back surfaces will be cut into opposing surfaces, but they will not end up looking like a blade until the final blade is carved. The Lakota blades have a 45 degree blade angle at the blade root and only 1-2 degrees at the tip. The blades weigh 620g each. This accounts for the rapid acceleration with wind energy changes. I will be making 2 sets of new blades, so both my mills will have the same rotor area. The new blades will make a new rotor dia of 2.8m. The blade tip will end up approx 25mm chord length, and 5mm thick. The aspect ratio will be higher, so blade efficiency may increase with the additional power. I am expecting an increase in rpm with the thinner blades, so tsr should be up, so maximum power should increase as well. The 1kW level may be achievable yet for a std F&P mill. I don't have any trees to cut, so will have to visit a lumber yard. Selecting some half decent timber will be the next step. The carving of the 5mm thick blade tip will also be a challenge. Gordon. become more energy aware |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Gordon, is there an online reference to the copy machine you bought? Thanks. |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi kiwijohn, I did a reply this morning, but the site went down, so my post ended up in cyber space. The gist of it was, the machine is second hand, and was not factory made. It is quite strongly made and has made many windmill blades in a previous life, so should work for me. Gordon. become more energy aware |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah the site was down for several hours this morning. I'm sort of stuck between a rock and a hard place with hosting of thebackshed. I'm at the mercy of Telstra outages. Sorry about that. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Glenn, no worries, I spent today in the big smoke. I am back home now, with some very useful wind blowing. I picked up some timber. I have enough lumber to make 8 blades, and it works out to $10 per blade for the wood. This is 50-100 year old seasoned Douglas Fir. I picked up 4 x 1600mm x 160mm x 60mm, 1/4 grain planks, with some minor nail holes. Still straight after all this time, with only a minimal, small connected knots. I have to saw them end to end across the diagonal. This will give me the 8 pieces. I had 2 lengths cut in half, so I should get 4 blades from the same plank x2, for 8 total blades. Hopefully this should keep the balancing to a minimum and give me a chance to pick the best 3 from each, with a spare for each. I will need to take care with the 5mm thick tips. Gordon. become more energy aware |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
Thanks Gordon, I will post a picture of mine when I think to take the camera downstairs. It is not very big but can handle any length so I guess windmill blades would be feasible. Bliming slow though.  |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi kiwijohn, here is a photo of the business part of the copy machine. The main rails are shown, and the travelling router with stylus and counter balance. 
This is a 1hp, 37000rpm router. I have to set up the original with blank. The posts [far right] are for precise alignments. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I have just finished the rough cutting for a new blade master. I have made 2 templates, one for each side of the blade. This has resulted in a much stronger template. The templates should not be able to flex in any way. I will post some pics when I sand them a bit. These are a tapered twist, with undercamber and thin airfoil section. The final blade will end up around 1.35m, with a flat mounting surface. I have a few options with cutting blades. One at a time or all of one side, and then all of the other. I haven't decide which way to go yet. The blade will be cut from a blank longer than need be, so alignment as the plank is turned over should not be much of a problem. The blades will not take much time to rough cut. I should end up with close to identical blades. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Well, I have made a start with making blades. Here is a picture of the two templates, the left light coloured one is mounted, as is the blank on the left, for shaping. The photo does not really show the twist and undercamber very well. 
The douglas fir cuts quite well, but does splinter. The last pass will need to be fine. Will upload a photo when a blade is finished prior to painting. Gordon. become more energy aware |
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feix62k Newbie  Joined: 30/07/2008 Location: AustraliaPosts: 36 |
Hi Gordon I would love some details on the router table setup Is it manual operated or CNC have you any plans or more pics of table and how it works as I am sure there will be lots of questions . looks real good nice blades cant wait to see the finished product thanks Shane dont the days seem lank and long when nothing gos right and everthing gos wrong |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
hi feix, I have made a test profile from the two templates. here is a pic, of the business end. 
The machine is not CNC. I would imagine this type of application would challenge any programmer. I have found that the rough process would be difficult with CNC. I have made jigs for each half, to aid the alignments of the two halves. I went 0.5mm too thin, so this will be adddressed in the next blade. I use an older cutter for the roughing. This is changed to a new one for the last pass. A light sand, and the blade is done. The flat mounting surface worked out well. The blade has taken a bit more time than I hoped. The weight has come in at 690g. This will go up a bit with sealing and painting. This is less than the 1kg that I had estimated. The blade has come out at 1.35m long, so this will make a rotor of 2.9m dia, once bolted to the rotor hub. I am hoping that the blade design will give a higher rpm, so I may have to use the series 80 rewire. This may increase the power to the magical 1kW, if the rpm increases from the 440rpm to above 500. The blades on the machine are currently 1.9kg each. The mill should be more responsive with the new blades. I have no plans to publish instructions to make the copy machine. The basic design is similar to the operation of a lathe, but without screw controls. If you see how a lathe is constructed, this is a start. The key is rigidity, and light weight in operation. Counterbalancing and linear bearings and large self aligning rollers achieve these goals. You should only use one rail in each dimension that has precise alignment. Gordon. become more energy aware |
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| KiwiJohn Guru Joined: 01/12/2005 Location: New ZealandPosts: 691 |
You say like a lathe Gordon, does the work and model rotate on your machine? I know that is how rifle butt making machines have worked for more than a century but I didnt see that in your photos and I have not made the "rotisserie" gear for my machine. |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Good looking blade Gordon , is that the finnished product or the template ? PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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