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Forum Index : Windmills : Please help me build a windmill!!
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| mrscott Newbie  Joined: 06/11/2011 Location: United KingdomPosts: 5 |
I would be grateful for any help and advice any of you could possibly give me during my attempt to build a wind power generator. I only want something small, just to charge up a 12v battery to add a little lighting and maybe some heat to a small shed i'm building and maybe to add a little heat to the greenhouse in winter. So, I've been learning a little about all sorts of things on this forum which has mostly added up to much confusion! I'll start with what i've got I suppose and hope you can help with questions as it goes along. Anyway, I have some Aluminium blades and a hub, and some nuts and bolts, and a rock solid post to hang it on. Now I need a motor....... Would this be any use? Or can anyone offer any alternatives at reasonable prices (bearing in mind i'm in the uk) Thank in advance!! 
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi MrScott No, that would be a terrible motor. Stear away from that type of motor, its too small and too expensive. I think you need to do a lot more research before starting on your first windmill. First up, work out how much power yor need. A few lights is easy, 100 watts of power could light up several CFL's, and you can build a windmill capable of 100-200 watts fairly easily. Heat is a different ball game altogether. A typical room heater needs 1000 watts or more, and that means a wind turbine over 3 meters in diameter in good winds on a tall mast. Have a look at the Links page, especially the wind related sites. http://www.thebackshed.com/Windmill/Links.asp#1 A treadmill motor ( go for high voltage and low rpm, ie 220v at 1500 rpm will be OK, but a motor rated at 120v, 3000rpm, wont be any good ) is a good starting point for a small 100 watt turbine, 1.5 to 2 meter turbine. Motors like the F&P Smartdrive or LG motors can get up into the 200 to 600 watt range, with a 2 to 3 meter turbine. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| mrscott Newbie Joined: 06/11/2011 Location: United KingdomPosts: 5 |
Thanks Glenn!
I was hoping to get the heat from a couple of divert load resistors - doesn't need to be too warm just to keep the frost off! I have actually acquired one of these for free here Apparently - "This Generator/Motor will make an excellent 12 volt Wind generator or hydroelectric generator. It has a short amp of over 20 amps at 12 volts. This motor is 1/2 HP continuous duty at 48 volt 10 AMPS with 7.74 inch pound of torque at approximately 4,000 RPM. 1.5 HP at 48 VDC intermittently . Not completely (AT ALL)  got my head round how much power this would make as a 12v system!!
Would that be a better start? Any clues what the above is all about??? Scott |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi MrScott Unfortunately these ebay sellers dont know what they are talking about, and selling items not suitable for what they say they are. Quick maths. That motor is rated at 48 volts at 4000rpm. A typical wind turbine runs at less than 600 rpm, and virtually never over 1000rpm, even in a storm wind 48volts divided by 4000 rpm gives us 0.012 volts per RPM. So to get 13.5 volts ( enough to charge a 12v battery ), it will need to spin at 1125rpm! So that motor is no good direct drive, it will never spin fast enough. You can gear it up 4:1, so its spinning at 1200rpm when the turbine is running at 300rpm, but then you are faced with a whole bunch of other problems. A F&P Smartdrive motor when modified, which we commonly use for wind turbines, can generate 0.1 volts per RPM. So at 300 RPM, a typical wind turbine speed, its generating 30 volts! That ebay motor would be making 6 volts. 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 |
mrscott You'd do well to heed the advice, "I think you need to do a lot more research before starting on your first windmill." offered by Gizmo. Creating a mere 12-volt charge is a much more daunting process than you've ever dreamed. If you think I'm kidding, check out how many times I've tried as opposed to how many times I've succeeded and you'll see it's not as easy as it looks. I'm in this 99% for fun, but if you're seriously looking for useful power, the key at this stage of the game is research. . . . . . 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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| mrscott Newbie Joined: 06/11/2011 Location: United KingdomPosts: 5 |
Cheers very much for the advice! I've been reading loads more and with what you've said re v/rpm, it's making much more sense! So, i'm now looking at treadmill motors and waiting for some details from some sellers! Thanks again! |
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MrDelanco Senior Member  Joined: 12/11/2011 Location: United StatesPosts: 101 |
Hello MrScott: View this video, it might help you. Building an alt. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
MrDelanco That was a great video. The only thing I see that could pose a problem is there is no flux-return pathway and most of the flux passing through and around the coil legs is wasted. I'm sure it will produce electricity, but if there were a defined return pathway, the output would be several times that of what's shown. A better way might be to mount the magnet rotor on the rim and use two planes of magnets with the stator held static betwen the two rotating magnet arrays. This would give a truer axial-fux presentation of the flux pathways to the coils. Of course, adding a second sheet of magnets will complicate the wiring something fierce. I have designed a true axial-flux machine (HAWT) that works very similar to the old telephone generators and if I ever get around to it, I'll post the build. I've had to tend to matters pertaining to "winterizing" my home before things get cold and nasty around here. Once that's all done, I'll settle in and finish the remaining 15% of the wind turbine build and post 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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| MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
Hello Mac; You might want to view the other videos. There are two planes of magnets, and some other modifications that you aren't seeing. Plus I charge an ultra capacitor bank between the rectifiers and the batteries and run another pma-flywheel setup from the alt-generator's output. I am totally off grid. This project was made from recycled items. I tried to show one way to recycle discarded items into a usable source of power generation. Alt up n running. Regards MrDelanco. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| mrscott Newbie Joined: 06/11/2011 Location: United KingdomPosts: 5 |
Thanks for the input people! I have another motor now which if i've understood will be good to go with the low wind blades I have. The motor is 180v, 1900rpm, 1.74amps, 1/3hp. Now ifi've got this right then to get up to charging a battery at 13.5 volts - it should only need to spin at 142.5rpm. How does that sound?????  |
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| MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
Hello MrScott Sounds like a lot of spinning for a small amount of power. You may not be able to get it to spin fast enough. Are you planning to gear it ? Regards Bob. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| mrscott Newbie Joined: 06/11/2011 Location: United KingdomPosts: 5 |
Really? I only want it to charge a 12v battery for me to run a few led lights off in the shed.
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