GORDONS' OTHERPOWER TYPE
WINDTURBINE PROJECT
Welcome to my windturbine page, I totaly got the bug for doing this after stumbling across a site in America have a look yourself maybe you will get the bug as well click the link below.
or the discussion site below
I decided to build an 8 foot wind turbine (start small and work your way up) The magnets I have used are 2 inch by 1 inch and 1/2 inch thick neodymium magnets, in britain these will cost about 5 to 8 pounds each, in America they will only cost you 2 to 3 pounds each plus shipping and VAT when they get here. This still works out at less than half what you would pay for then here.
I ordered my magnets from Magnet_Master, see them on ebay, 24 magnets cost me $84.00 thats about £42.00 plus shipping $70.00 plust VAT £12.00 I dont think customs and excise know how to use a calculator or they just assume that nobody else does. should have been £7.35, never mind though at least I had still saved a substantial amount.
Whilst I was waiting for them to come I set about making my blades, the timber I used for these came from a local builders merchant I was quite lucky as they had some special order timber returned unused, hardly a knot in it almost cabinet grade timber 2inch by 9 inch. see the pictures on the left click on them for a larger view. I did most of the shaping with my hand held power planer only using a chisel at the root end, flat planers dont do curves very well. I managed to get 2 1/2 blades done and had just turned the last one over to do the back and what had to happen? yes sods law the belt on my planer broke, oh bother I said( or something like that) I knew I had a spare in my workshop somewhere in fact I had seen it only a few weeks ago, could I find it? not a hope in hells chance I had sorted my workshop out at least once since then. it could be anywhere now. I ordered 2 new belts and a new set of blades as well, I have had this planer for about 12 years and it has been used and abused and I am still using the original blades that came with it (it's a skill planer) bloody brilliant.
Meanwhile I get impatient and decide to finish the back off with my 9 inch hand plane, it took me a whole day to finish it by hand and balance all three up so they wieghed the same.
I then moved onto the head ( the bit the hub fits to) I had a bit of old pipe from an old swing and a bit of box section steel from an earlier project, I bought a new hub and shaft from a trailer place, apart from a few more substitutions the head came out quite well but I will probably make a new beefier one up if I ever fly my windturbine, this one will do for testing.
My magnets came so I got on with the rotors, I couldn't get hold of any 11 or 12 inch disks so I had to make do with 10 inch, this leaves only just enough room for the threaded rod to clear the stator about 1/8 of an inch all the way round but it should be ok. in the picture on the left you can see I made a template from some hardboard I had lying around, before I stuck the magnets on I assembled both the disks onto the hub and used the grinder to grind a mark into the edge of both disks to make it easier to align the magnets, I made a mark on the template and lined that up with the mark on the disk. The magnets on one of the disks have to go N S N S and on the other disk they go S N S N so that when they are assembled on the hub they pull on each other. I used an epoxy glue to glue the magnets down a slow setting one as they are ussualy stronger when set than fast set epoxy, I let the glue go off enough to hold the magnets from pulling each other out of place then moved the template to the other disk making sure I line up the mark with the notch in the disk.
I then made the mould that would be used to cast the stator in, this is 14 inches in diameter made from 12mm plywood given a good sanding and sealed with polyurethane varnish just a light spray didn't want to varnish it just seal it, I then gave it a good rub with some skotch pad to denib it, the next step was to polish it to do this I used Briwax a good coat left to dry and then polished up followed by 3 more coats of Briwax polished in between coats. This should stop the resin sticking for ever. The bit of ply I cut out of the mould is to be used as a lid see pic.
I had a bit of kitchen worktop and cut it down so that it would fit both sides of the mould, the bit for the bottom had a piece of wood fixed to it so that the clamps would fit under so that I didn't have to start lifting it to clamp it, these would also stop the clamps from pulling the mould out of shape.
I poured the stator put the lid on and the worktop and clamped it up good and tight 8 clamps should be enough. Now for the wait(will it come out? have I wasted all that copper?) so many things go through your mind at this stage but all you can do is wait. Well 2 hours later it was pretty well cooked and ready to come out, it came out really well all that polishing hadn't been a wast of time after all.
See pictures. I had quite a bit of spill as I had managed to compress the coils even more than I had hoped for. The stator is just under 5/16 of an inch thick. The coils are 2 in the hand of 17swg this is about the same as 15 awg 42 turns, I arrived at this after making about 10 test coils tested with both rotors on the head and this is what I decided on.
The stator cleaned up realy nice I used a diamond bur in a mini drill, made the task easy.
I assembled the alternator on a test pole in the workshop for testing and checked a few voltages I star wired it initialy and found I was getting cut in for 12 volts charging at around 118 rpm rising quite rapidly to over 30 volts at around 200 rpm. I then wired the stator in delta (see diagrams for configurations) and was getting 12 volts charging at 140 rpm but only rising to 18 volts at 200 rpm, star wired = more volts less current, delta wired = less volts more current.
However, after talking to flux via the fieldlines discussion board I learn't that these were to low speeds for cut in and was advised to alter the gap between the magnet rotors.
After altering the air gap to aprox 5/8 inch I was seeing cut in 12 volts for charging at 150 rpm wired in star configuration and cut in 12 volts charging at 190 rpm wired in delta configurationjust charging a battery.
With a load on (12 volt 50 watt halogen bulb) in paralell with the battery I could still spin it up by hand in star to 12 volts charging at 200 rpm but with it wired delta I couldn't spin it fast enough to get past 7 volts at 230 rpm. I have decided to leave it star wired and see how it performs in the wind I can always set the tail wieght so that it furls earlier.
I now have the machine set up on a test pole in the garden but, unfortunately there is no wind and has been no wind now for over a week, really strange for here.
I set up a bicycle speedo to measure the rpm, I initialy set the sensor over the rear rotor to use the magnets but couldn't figure the right number to program for wheel diameter, so I now have a small neodymium magnet glued to the back end of one of the rotor studs and have mounted the sender on the rear hub support bar. This seems to work when measured against the second hand of a clock turning by hand but, I had to use a wheel diameter of 835mm not the usual 1670mm, I guess that the Halfords speedos are calibrated differently.
Well then still no wind but am promised 15mph on thursday meanwhile I have added a few more pics in the picture frame to the left.
Still to come more pics and real life testing.
Will post more as I get done.