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Forum Index : Windmills : The Column 700w-3b-12f VAWT
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| itsandbits1 Regular Member  Joined: 13/08/2010 Location: CanadaPosts: 81 |
sorry you were too slow. I took the one of the 78" down I was giving too much away on it, I have to get new vid. the units would easily put out more as you can see, if the wind is there; and not very much either it spins up easily under load the whole way and with the magnet cogging too.I am going to build a proper alt. Might even use iron core because these wings have some start up torque too. the hand brake takes a while over 1mps and puts the wings out of line. only way to stop it becuse shorting it out doesn't do anything. They are a heavy lift wing. The little one in the vid happily spins away lighting those leds in .5-1 mps winds all day/night long and have been through 40mph and the total weight is 1 lb for all three. |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=itsandbits1] . . . only way to stop it . . . It seems you could rig some kind of a curtain or solid wall that slides up a slot and is then able to be positioned upwind of the blades, blocking the wind flow to stop it in an emergency. Maybe even a symmetrical-section wing on a vertical hinge with a hand lever at the bottom. Its normal position would be to "float" pointing into the wind ahead of the blades and it could then be moved by hand to deflect the flow away from the front of the mill. Of course, something like this would have to have its own bearing independent of the main shaft, allowing it to stay in the changing wind flow until needed. Just a thought. . . . . . 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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| itsandbits1 Regular Member Joined: 13/08/2010 Location: CanadaPosts: 81 |
This is someones elses thread so my mixed up message was I would take discussion of my mills elsewhere but it sure got posted strange. in a general sense though for any wawt; this is a cross between a hawt and a vawt, a wind shadow would help but what I meant in the case of these is that they are test platforms and on a working nit I will put a brake and all units of any configuration should have one. Thanks for the reminder |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
You are going to love this one.. at 6.5 was going 390rpm and that was the last measurement I made before it took off. I am not going to be able to measure it with no load at higher wind speed, because too dangerous. so I need Your best guess at the RPM that you see in the vid. later I measured the wind speed and at the highest I got 11.5 m/s and that was a gust of wind, but lets say that when it was spinning the wind gust was at 11m/s so what is your guess of the rpm at 11m/s? Youtube link I have some damage done to the blade edges that I have to resin to fix. I promise I will never let it spin with out a load ever again at that wind speed. BUT DAMN THAT WAS FUN. regards sam Many Ideas One Brain. http://www.wrapwind.com |
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Big Al Newbie  Joined: 06/10/2010 Location: United KingdomPosts: 38 |
Sam, you think it 's scary up that nice solid tower. Not half as scared as I am for you when its spinning. have not followed all this thread and don't know materials but I would n't get too close unless you're pretty sure its going to hold together. Those chips you mention would n't have done an eye much good if ejected at speed. Be Careful. I'm usually reckoned to be a bit foolhardy but I would n't be too near that. O/P looks good but unloaded may give a false impression. Big Al Every Day is a school day (even at 67) |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi faroun, I have seen the video and there are some serious balance problems that are propogating into even the support structure. These VAWTs seem pretty dangerous to me. I have never seen a HAWT behave this badly. Be Safe with your experiments. Gordon. become more energy aware |
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Perry Senior Member Joined: 19/11/2009 Location: Posts: 190 |
Weeeeeeeeeee. That thing was humming. Echo all the sentiments. Protect yourself. Please finish your alternator or at least put a tape drive motor or geared auto alternator on it....something. I just don't see the reason to run any turbine in a dangerous unloaded overspeed condition. All this high rpm craziness gets thrown out the window when you put a load on it. You won't see more than 100-200 rpm once loaded then all your balance problems go away anyways. It seems like you are optimizing for a condition that will never exist when your turbine is completed. Please be safe. Perry |
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| Ghetto Newbie Joined: 01/09/2009 Location: AustraliaPosts: 14 |
Hi Sam, Out of interest how did you get it better balanced in the latest vid?. Also what bearings are you using? I'm not from a mechanical background and seem to struggle in that area of shafts and bearings when building a small savonius a while back. I used skate bearings at the time but I wanted to know how to setup a stronger bearing and shaft arrangement, eg Perhaps i should of used a pillow block bearing to support my VAWTS weight? Cheers, Rob |
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| faroun Regular Member Joined: 18/09/2008 Location: Posts: 62 |
i used tension wires inside the turbine to compensate what the shaft is lacking. i am using regular 1.25" bearings, nothing special, the special part is the housing it is sitting in. the pillow bearing are no good for my turbine, they twist and turn way too much. regards sam Many Ideas One Brain. http://www.wrapwind.com |
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