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Forum Index : Windmills : I have a really stupid question.
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Sonny Regular Member  Joined: 17/01/2010 Location: United StatesPosts: 66 |
I have everything I need to build a generator using the 2x1x1/2 magnets and as you know these things aren't cheap. What I am wanting to do is build a smaller generator using some 1 x 1/4 inch N42 disk magnets I have ordered. What I can't seem to find is what gage wire to use and how many turns in the coils. I'm hoping to build this as a learning tool before I start on the big sucker. Any help you could give me in this mater would be very appreciated. Thanks Sonny a complete novice |
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Downwind Guru  Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Have a look at the current topic "Winding coils " in Electronics. Pete. Sometimes it just works |
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SparWeb Senior Member  Joined: 17/04/2008 Location: CanadaPosts: 196 |
Hardly a stupid question. Rather challenging, in fact, because any choice you make becomes a trade-off. Since you're committed to making a small alternator with the 1" disks, you should aim for a design the suits them. That will depend on the number you have, for example. Then they have to be spaced apart on a pair of disks - the spacing is going to affect how big each coil is going to be, so you have to plan the magnets and coils together. Spacing the disks apart is also a trade-off. If they're close, the magnetic field is more intense, but there's less room for the windings of wire to fit between. Farther apart there's more room for the coils, but you've lost some field intensity. There is a trial-and error process that you can use to get the best of this, but it doesn't come easily to the first-timers (like me when I was trying it). Lastly, the wire itself - your original question! Since the pitch of magnets defines the space between coils, and the space between disks defines the thickness of the coils, the total volume is now limited. Fill that volume with either a) lots of turns for high voltage, b) thick wire for lots of current, or c) a balance of both to set just the right cut-in speed for a typical blade and battery voltage combination. Easy as pie? And you thought it was a stupid question! Steven T. Fahey |
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isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
You might want to look at some of the conversions to the delco delcatron alternators 10 si etc. With your machine shop you could make up the rotor and rewind the stator to suit The 2x1x1/2 magnets should work for this. Nope no stupid question's this is how we learn ! There are people that read these forums that dont post but our what seems to be a stupid question helps others as well. I think we are having FUN ? URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| Sonny Regular Member Joined: 17/01/2010 Location: United StatesPosts: 66 |
Thanks for your help guys. I guess I need to get myself lot's of different gages of wire to experiment with. that stuff is hard to come by around here though. I need to start looking for some old motors or anything I can rob the wire out of. I am starting to think I may have made a mistake already on the wire I ordered for the big sucker. I found a 50+ lb roll of 13 gage magnet wire on ebay. I since learned that most are using 14 or 15 gage wire for their alternators. I guess I will have to work with what I have now. again thanks Sonny a complete novice |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Gage wire ?? I must be dumb as i can never get my mind around it. Can someone give gage 13-14-15 in mm dia. please. As for sourcing wire, old microwaves are a good starting point with 1.1mm primary windings. The secondarys are much lighter wire but you could wind 2-3 strands in bifolar to get a simular result. Pete. Sometimes it just works |
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Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Downwind; Wire Gage Conversion, American wire gage to metric.wire chart Edit; More reference Number 12 AWG was standard US house wire for many years, Fused at 20 Amps. can handle 28 in a motor There was a change in the electrical code that permits 240 volts on the cable which is split to 120 volts at the outlet and the other leg is branched to other outlets. This is a 4 wire cable (AWG #14) fused to 15 Amps. The Larger the gage number the smaller the wire. Time has proven that I am blind to the Obvious, some of the above may be True? |
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oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
An excellent source of thin wire is to be found in the degaussing coils in any and all tv sets and CRT monitors. Thin wire is fine to use, it just means after establishing the best turns number, you wind 2 or 3 or 4 wires in hand to make up a coil of the correct copper cross section you are after. So if you find you need 100turns of wire, and using the thin stuff you have gobs of room, wind the same coil using 2 or 3 or 4 wires in hand, until you find out how many "in hand" wires fills the winding window available. As it turns out, thin wire many in hand is better than a single thick wire when you go larger than about 1.2mm, as you can get eddy currents in the thicker copper. (think Litz wire). The frequencies we encounter will be unlikely to cause skin conduction on the thick wires, so I don't see that as a problem. I also got hold of a 50lb roll of #13 wire (or thereabouts) and it has proved to be an excellent choice for my 4meter machines. For your test machine (little one) degaussing wire will do a fine job, probably only 2 or 3 in hand or so.... and it's free. You don't have a lot of magnet to work with there so only a small prop I would think.... unless you like burn't stators and runaway excitement. The bigger the TV, the more wire available..... happy hunting. ..........oztules Village idiot...or... just another hack out of his depth |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Thanks Greenbelt, Printed and laminated. Pete. Sometimes it just works |
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| Sonny Regular Member Joined: 17/01/2010 Location: United StatesPosts: 66 |
Thanks a ton Oztules, now I don't feel so dumb about ordering all the 13 gage wire. And you would tell me now about all the wire to be had in the TV sets, my son just threw out a big 32 incher dang it.   a complete novice |
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| Bernhard Newbie  Joined: 01/02/2010 Location: CanadaPosts: 12 |
I assume this is for a wind mill... That's how I started out!....with first building a generator and then the wind mill. Unless you match both you can be in for a lot of dissapointments...and also waste a lot of good copper wire....or magnets. So after my first disappointment I built something like a "test-bed" wind mill. Its a 8 foot diameter 4 blader. I made the blades from 2 2X6 planks....and not by "hand carving". They are a laminate construction and are as strong as National Leage Hockeysticks! Start out by cutting 6 mm thin strips from an 8 foot 2X6 on a table saw. Then stack the strips and drill a hole at the center for a holding bolt. These strips are then stacked with this bolt going thru the center. Now you "fan" the strips just like You fan a deck of cards. What you get is a "stair case" where the (unfinished) prop pitch varies smoothly from 90 deg. at the center to whatever You want at the prop tips. I purposely selected 20 deg at the tip, because I wanted a low rpm, hi torque prop. Laminate these with a good carpenter glue and after the glue is set run an angle grinder along the surface till the "steps" disappear. Aside from waiting for the glue to harden I can make a set of blades inside 2 hours and waste no wood other than the sawdust from the table saw kerf. These blades come out with precision and I balance mine the same way You would static balance Helicopter blades...hanging from a wire and positioning a weight you can screw on...I simply use 1/2 of a door hinge. As a hub I use 4 crossed pieces of flat steel and welded the back cross to the pedal crank of a scrapped mountain bicycle. Why you may ask... Actually I have 2 such pedal cranks on my "test-bed" with 2 gear clusters as well. With this arrangement I can select a gear ratio from 1:1 all the way up to 12:1. 
Laugh about the vice grips and clamps if You want, but remember this is my test rig and I clamp all sorts of Alternators, PM DC Motors etc there to see how much cogging and drag there is. Also I paid zero attention as to how ugly this rig looks. Dr.Porsche said "form follows function" and the function is testing...also to see at what wind speed this rig disintegrates... so far so good...I let it free wheel in winds over 80 Kmh and nothing failed so far. When I upgrade my 8 foot to a 16 footer, then I`ll spend some bucks to make it look pretty...not before! 
The stand is from my old 10 foot C-band Satellite Dish. I have had anything from automotive alternators, to self wound alternators up and running on this test rig... We get Winter storms with winds whipping up to 100 kmh at -40 and colder temperatures ( high density air!!!) here in Manitoba... and nothing has failed me on this rig... save for one bicycle chain that snapped when I tried to stall this mill by shunting the current from the generator at such a wind and at the highest gear ratio. The chain drive has very little drag= 8.3 grams at 120 cm (the tip of the blade) The unit You see being tested in the picture is a converted 1/3 hp single phase furnace blower motor I found in the local dump. I salvage magnets from old hard drives and cut them with a Dremel tool in half....else you have conflicting polarity when you use them in slits on a rotor. Then cut 8 slits with an angle grinder in the rotor of a motor as the one shown in the picture. Mark out 4 lines at 90 degrees on the rotor, then cut a slit, wide enough to insert the Harddrive magnets on each side of each mark...makes a total of 8 slits. Arrange the magnets so that equal poles face each other! ...so they repel and don't shunt their field lines. You will then notice that the segment of the rotor between the magnets is now strongly magnetized. On the next 1/4 Quadrant section reverse the Magnet Polarity, but these must face each other also, so that they would repel. After that connect the starter winding with the main winding in series. You now have 3 wires with one center tab. The main winding of course gives you the best amps and the starter +main in series the highest Voltage. These butchered Hard drive/single phase motors are the simplest and most hassle free dynamos and cost nothing! I am in the process of converting a 1 Horse table saw motor, where I can fit 4 hard drive magnets per slot. No way would I ever go back and spend time winding coils after I tested a few of these converted motors. No way would I ever go back and wind coils |
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Oztules Is that the old televisions or is there enough wire in the new digital and hi definition sets ? Lots of the later model analog ones around cheap or free URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Bernhard, Interesting read of what and how you done things. Be nice to see some photos of the magnet conversion you do on the next motor. That looks to be a hell of a lot of twist in those blades. I would think they would be rather noisey with a few rpm on them. Sounds like a very practical way to make a set of blades with the ply. Pete. Sometimes it just works |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
I would say Oz means the analog tvs and monitors as i dont think you will find a degaussing coil in a digital tv/display as there is no need for them. The bigger, older, ugly, the better i would say. But any analog will do. If you knock the back off one you can remove the degaussing coils roadside, no need to drag it home. Pete. Sometimes it just works |
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| oztules Guru Joined: 26/07/2007 Location: AustraliaPosts: 1686 |
Just to clarify, what Downwind has said, there may be confusion so I will put it like this. If it has a picture tube in it, it will have degaussing coils. They appear as a thick black insulation taped up bundle of wire around the screen periphery and crossing over the back of it as well sometimes (on the bigger ones). It is simply a matter of snipping off the wire ties from the skein of taped up magnet wire and taking it home.... no enamel or anything to mess you about. So whatever they print on the front, if it has a Cathode Ray Tube for the display (deep heavy TV to hold the tube) then it's jackpot. Bigger is best. Same with computer monitors. If they are CRT (picture tube types) not LCD ones, then they are a good find too. (lots of goodies inside... fets, caps,switcher ic's etc etc.) ..........oztules Village idiot...or... just another hack out of his depth |
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| Bernhard Newbie Joined: 01/02/2010 Location: CanadaPosts: 12 |
I was just going to upload a few more pics to photobucket when I've seen Your post. That "twist" on the blades is what gives you the performance and they are quiet!!! very quiet because of it. Look at how a prop on a Herc C 130 looks like or a prop on a "quiet" sub....same idea. As the radius increases the pitch must be a linear function of radial velocity...if you would use the same pitch from center to tip and rotate, then the tip would want to push air faster than the zone next to it at a lesser radius....which would then create turbulence, less torque and noise. The only noise coming from the rig is from whatever generator I am testing when I use a high gear ratio. Then the chain running over the sprocket at high speed is audible....much like if You stand a bike upside down and crank the pedal as fast as you can. Taking pictures in my basement workshop when I convert a motor is a bit tricky...the video cam I use takes very blurry pictures indoors...and outdoors here its still -25 degrees. But the whole procedure is really simple. First I mark 4 longitude lines in 90 deg Quadrants on the rotor of any such type induction motor (if it is a 4 pole with a 90 degree winding step). then I use an angle grinder and cut a groove deep and wide enough on each side and as close as possible on each side of these lines....just so there is enough "meat" left between a set of cuts. The ideal cuts are when the "meat" section between the pair of cuts is as wide as the stator groove that holds one side of the coil!...then this sections filed lines "cut" the windings of one side of the coils with say a south pole, when exactly at the same position a north pole "meat" section passes by the other side of the same coil in the stator. After I finished all the cuts (8 for this example), I slide the Hard drive magnets (cut in 2) in so that the south poles for example face the south poles in the adjacent slit. These hard drive magnets have a "boomerang" shape and each side has a north and south pole and the reverse on the flip side.. that's why You have to cut them in half. When all 8 slits are "packed" I epoxy the slits... let it cure. Then put the rotor into the chuck of a drill press and spin it up. "Kiss" the epoxied rotor with the angle grinder, holding the disk flat and clean it up...a lathe works better but I had to leave mine in the Yukon when I moved south. But sure, the next time I promise I`ll take some pictures. I am pretty sure though You have no trouble to picture the entire process in Your mind in the meantime. I am also building a steam Turbine at this time. Am still looking for a good "squirrel cage" centrifugal blower (in the dump). I already built and installed the wood fired (100 psi) boiler in my basement. At least I think that's what a "recycled" gas fired hot water tank can take...I hope I`m right but will hide under my work bench when I try it at 100psi. I did have it at 80 psi and heard no "Das Boot" noises! So from now on even my garbage =btu's = Kwhours. So between the solar on the roof, the windmill and the wood fire powered steam turbine I should not be suffering too much the next time the power grid fails... happens here often in the Winter! I got the idea for the steam turbine and using a centrifugal blower when I watched this video: http://www.instructables.com/id/RC-Steam-Turbine-Tank/ after I saw it I was HOOKED! I tried it out with compressed air coming out of the blow gun at just 40 psi on a small centrifugal blower and now I am staying up at night imagining how much power You could get with 3 steam nozzles on a 8 inch rotor!!!! But I figure I better wait till I get my Lathe & milling machine again for this project. |
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| Sonny Regular Member Joined: 17/01/2010 Location: United StatesPosts: 66 |
WOW You guys make me feel like a kindergarten kid when it comes to this stuff. Thanks Bernhard and to all who replied. I also feel like a kid in a candy store, with all the information on this web site. a complete novice |
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| Bernhard Newbie Joined: 01/02/2010 Location: CanadaPosts: 12 |
I am curious how much these magnets cost you. Stuff like that is hard to come by in Canada. Canada is unfortunately one of these countries that "price dumps" on the U.S. and recoups by charging above premium prices for substandard products in the domestic market... For ex. I have seen premium Canadian lumber at ~ 60% the price in the U.S. of what we have to pay for sub-grade here. Hydro=same story. Oil=same story. I would love to get my hands on a stack of these magnets you mention. Shape does not matter to me...I can adapt. So far my best source are junked computer hard drives. But I need quite a few for my next project and it stalled for that reason. Buying in the U.S. and having it shipped here is not really an option. Canadian customs penalizes that with a duty high enough in order to force you to a local rip-off retailer. By the way I also still feel like a kindergarten kid! ....every time my mill spins up |
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AMUN-RA Senior Member Joined: 10/03/2007 Location: AustraliaPosts: 144 |
bernhard try looking at the latest series of mith busters look for when they blow the hws think it went to 300+ psi before it blew through a 2 story house be careful what u do with stored pressure ptr valves are good insurance mick Every day the sun shines & gravity sucks= free energy. |
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| Sonny Regular Member Joined: 17/01/2010 Location: United StatesPosts: 66 |
Bernhard, I am buying my magnets off Ebay. That is the only place I can find them for a reasonable price. But even there you have to watch the shipping charges. If you do a lot of searching, you can find some pretty good deals. I just bought these magnets yesterday. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120522280 330&ssPageName=STRK:MEWAX:IT I payed a little more for bigger magnets all because the other guys' charges were twice this for smaller magnets. Check it out, but be careful of the shipping charges because I'm sure they will charge more for the shipping to Canada. One other thing, I went this route too and looked into buying them wholesale. I couldn't find one company here in the states that manufacture the magnets. Everyone of the manufactures were in China. And to buy them wholesale would mean a very large dollar outlay. a complete novice |
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