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Forum Index : Windmills : Windmills for hot water
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Crew I faced the magnet wheel and ran aluminum, brass and iron-backed aluminum (3/16" thick") at less than 1mm from the wheel. Again, it DID get warm to the touch, but not much. I ran the headstock at just under 600 rpm to more accurately simulate real windmill conditions. Next, I mocked up an axial-flux arrangement with some magnet wheels from former builds and ran the 3/16" aluminum sheet in the fields and it may have been a 'little' warmer. Running with the magnets facing N-S-N on one side causes my little lathe to labor some, that is the rpm is noticeably less, but with the axial flux situation, with each ring iron-backed to concentrate the flux pathways, the little lathe slowed way down. Unfortunately, my little lathe's 12-volt d.c. motor got warmer than any of the plates! 
I'll keep dinking with it, but I don't forsee any need to run out and patent the idea anytime soon. As for using it in any practical application, I think it would be better to wind a stator with overgauged wire and run it as a dead short through a heating element either submerged in water or in close contact with the water tank. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I think you are right Mac, This is one where theory and practice are keeping a wide berth of each other. I had a little surf on the web looking for a few pointers and found plenty of low power high frequency induction heaters using capacitor banks to tune a resonant frequency. Only one I found running at 50 Hz and that was designed as a steam block for instant hot water. There was no technical detail so they are probably still in the patent process. If I spot an induction rice cooker at a garage sale for $2 I might have to buy it and strip it to see how it works. yahoo I'm confused, no wait... maybe I'm not... |
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| electrondady1 Senior Member  Joined: 12/02/2009 Location: CanadaPosts: 208 |
macguiver. from your earlier description, you have the mags inserted into a plastic disk. would you consider placing a flux return path for the back side of the plastic disk (such as a saw blade) it should give you a bit better projection out the front towards the aluminum plate |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
electrondady1 I tried that already. It helps, but the contraption still only makes the pick-up metal slightly warm even with a good flux-return pathway. I even tried another axial-flux magnet plate that has 24 magnets; same results. If I were to spin the mandrel at 1500 rpm (unreasonable for wind-driven) it would likely get hot and I think that's what was done in the replies that said the metal got hotter than could be handled with bare hands. It makes sense, but like I said, I wanted to be able to accomplish useable results with shaft speeds more comensurate to traditional windmill shaft outputs. I think I'm going to take Megawat Man's advice (page 3) and try an iron plate, since the flux fields will readily penetrate the iron and cause more internal "friction" if that's the right word and create more heat than with a soft metal like aluminum or copper. . . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hey Mac, just as an experiment, spin it at 1500RPM. See if it can get really hot, that will prove the concept, even if not practical. If it does get hot, then maybe you just need to triple up the magnets, move them further out from center, etc. I think it has to work, we just need to work it out. If it were a axial flux stator, sorted out, it would get so hot it would start to cook the epoxy. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Glen I don't doubt it works, it's just I want it to work at a more-feasible shaft speed and 1,500 shaft rpm from even a HAWT is dreaming unless I use gears and we all know where that one winds up (hint: the tip)! Thanks for your input. I'll keep tinkering with it. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| Pierre159 Newbie  Joined: 23/02/2021 Location: FrancePosts: 1 |
Hello Mac, hello all, i'm working on average the same project to make hot water with induction on a windmill, do you have continue to work on this project? do you have some idea to make it ? i would be pleased to share with you my construction. brgds |
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