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Picture of DIY 1000 watt wind turbine
We built a 1000 watt wind turbine to help charge the battery bank that powers our offgrid home. It's a permanent magnet alternator, generating 3 phase ac, rectified to dc, and fed to a charge controller. The magnets spin with the wind, the coils are fixed, so no brushes or slip rings necessary.

Update: DIY Amp Hour meter for monitoring charge!

All about homebrew wind and offgrid power systems, the complete reference!
 
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Step 1: Build the magnet disks

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We had 12" steel disks hydro cut. We cut a template for mounting the magnets. Then we mounted 12 grade n50 magnets around the outside edge. We then built a form, and poured the resin with hardner.

Step 2: Build the coil disk

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We wound the nine individual coils, soldered them in a 3 phase wye configuration, and encased them in resin. We used 35 turns of 2 parallel strands of 14 gauge enameled (magnet) wire for 12 volts. Use 70 turns of single strand for 24 volts. # 3 phase diagram shown here shows 3 stator coils. each of those coils is actually 3 coils in series. coils 1,4, and 7 are series together, 2,5, and 8 are series together, and 3,6, and 9 are series together.

more details, see the following page 15 for the series star, 1-y diagram.

http://groups.yahoo.com/neo/groups/axialflux/files

AXIAL_FLUX_HowItWorks.pdf

Step 3: Build the bearing assembly

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Two Harley Davidson wheel bearings are inserted into the pipe, with a smaller pipe locked between them to keep them in place.

Step 4: Construct the blades

The blades are 2" x 6" pine, cut at 10 degrees on a table saw, and sanded into a rough airfoil. Not perfect, but close enough.

More can be found at

http://tech.groups.yahoo.com/group/axialflux/

http://www.green-trust.org

http://youtube.com/watch?v=o9EEHFKEckM

Step 5: Further Reading

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davedpilot11 days ago

Thanks sspence, I'm a complete newb regarding this stuff. Can I buy the rectifier somewhere or do I need to make my own?

sspence (author)  davedpilot10 days ago
You can find them online, or build your own like this own - http://otherpower.com/rectifier.html
davedpilot11 days ago

I designed this as a proof of concept and wired it in a star configuration. I used 20awg with 50 turns each on the six coils. The diameter is only about 5" so I don't expect much, but like I said, I just wanted to if it would work. What kind of 3 phase rectifier should I get for this if I wanted to convert to DC? Any help would be appreciated and if you have questions let me know.

Thanks

Dave

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sspence (author)  davedpilot11 days ago
just six diodes wired per the diagram in the instructable. just like a car alternator diode bridge.
davedpilot11 days ago
AndreasV1 made it!12 days ago

Can you please look at my problem the document is in the attachements.

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sspence (author)  AndreasV112 days ago
The magnets have to be style A, and your wiring is wrong. every third coil is in series. one end of each series connects together with one end of the other two, and the other end of each series comes out of the alternator.
MVR00713 days ago

Would you be able to build this possibly using only 12 magnets in all with 6 on each magnet disk? I'm assuming that doing so would decrease on the power output in the system but would it still work as a alternator?

sspence (author)  MVR00712 days ago
I suppose it might work, but all the parameters would off.
I know that programming water jets to cut a out a particular pattern cost quite a bit and so I was wondering if  you would sell the precut disc to those of us who would like to build their own wind turbine. I believe if you were to sell the precut disc, they would help offset the initial cost of programming that you incurred. I can cut them out, but to get the correct balance would take some time that could be better spent on wire winding. Thank you for the information that you have posted and I hope that you might consider this.
sspence (author)  HariKarier11 25 days ago
I don't have access to a water jet any more. You may want to look around locally.
PatrickJ41 month ago

Thank you for the answer. If you bear with me I some more questions, I appreciate your help.

I have enough 14 AWG wire to make 18 coils of 70 turns each. Before starting anything I would like to know if 6 coils per phase wouldn't be a too long wire. Could I parallel them in 2 pairs of 3?

I also hesitate between one rotor or two rotors. Because I have 48 magnets I would need 2 huge steel plates (24 magnets/each rotor) that will be very heavy. Could I get a similar result if I used one single rotor for all the 48 magnets like a bicycle rim? I would lose flux but i guess I would gain speed since in one revolution 48 magnets would swipe the wires instead of 24.

PatrickJ41 month ago

Hello, please tell me if my understanding is correct: If I have a 12V battery system, when the turbine starts spinning it will create voltage. As long as the voltage is lower than 12V no current will flow to the battery and the turbine will spin relatively easily. When it generates 14V, the battery will bring the system down to its own 12V by drawing the extra 2V as a current and the turbine will be slowed down proportionally with the amps that flow through its wires. When it generates let's say 28V the current that will flow will be caused by the 28-12=16V, so the amps will go up slowing the turbine more. My question is : If I put a 24V battery system then the current that will flow will be caused by 28-24= 4V so the turbine will not be as slowed as in the case of the 12V battery?

sspence (author)  PatrickJ41 month ago
That sounds about right. Which is why, if using a 24v system use one strand of wire instead of two, and double the number of windings.
windrage2 months ago

i converted a house fan into a turbine, how would i go about adding a ratio system to it?

sspence (author)  windrage1 month ago
House fans don't generate electricity. This instructable is about building your own alternator.
someone12232 months ago

If you added more magnet disks and coil disks, would that create more power output? Or would you be better off just making more turbines?

Also can anybody point me to a place where I can get more information on setting up the rectifying diode pack and battery bank?

sspence (author)  someone12231 month ago
http://www.green-trust.org has lots of articles on batterys, controllers, and off grid systems.
sspence (author)  someone12231 month ago
it could increase voltage, but everything would have to be recalculated. rpm, wire size, the works. Better just to build another turbine.
NicholasG42 months ago

http://www.supermagnete.gr/block-magnets-neodymium...

Would This Manget Work? Please Answer

sspence (author)  NicholasG41 month ago
Probably.
DaveyH1 month ago

How much did it cost you overall? We're considering getting wind and solar energy for our house, but we're working out the numbers right now. So far it's been pretty good, we just have to work out getting enough power as apposed to just getting wired to the grid. I'd personally like to keep our power bill to zero, so we'll probably go this route anyway. Once we get the paperwork out of the way, we'll get to work on building one of these

http://www.sweeneyelectric.net

sspence (author)  DaveyH1 month ago
About $1200 with tower. Prices have gone up over the years.
NicholasG42 months ago

http://www.supermagnete.gr/block-magnets-neodymium...

Would This Manget Work? Please Answer

roger.marlowe2 months ago

I saw the economy almost go completely down in flames in 2008 and it made me feel very vulnerable to realize how dependent I am on central power and the grocery store. We also just had a pretty rough winter here in TN and several times, I waited through the ice storms to see if the grid power would fail; more dependency.
I need a passive solar home and power generation capability simply for peace of mind.

JohnT124 months ago

I'm curious as to how you determined that this is a 1000 watt generator. I'm working on a small model right now and am not sure what I'll get from it when it's done. About 5 inches in diameter.

I must also say that I've given up completely on lead acid batteries. When yours give up the ghost, check out LiFePo4 cells.

sspence (author)  JohnT124 months ago
Ohms law. number of coil turns, wire gauge. rpm. blade length, wind speed.

Not interested in Lithium based batteries. NiFe, yes.
JohnT12 sspence4 months ago

Thanks for such a quick answer. I also assume the power of the magnets play a factor. I'll have to look in to NiFe batteries. Sounds interesting. I love this stuff.

John kb8uhn

hawks88 JohnT123 months ago

NiFe batteries are pretty outdated. I had to do a quick google search because in this industry, you never know, old tech could make a resurgence, but I didn't see anything. They're basically the armored tank of the battery industry. You can abuse them and they'll last a long time, but they're not that cheap, they have half the energy density of lead acid, and they have issues with holding a charge.

sspence (author)  hawks883 months ago

NiFe batteries have witnessed a recent resurgence with companies like Iron Edison and Be Utility Free producing improved pocket plate versions that are more efficient (75%), and don't self discharge as quickly. They are the the cadillac of batteries because it's almost impossible to kill them, and they can last 50-100 years or more.

Calderick3 months ago
I am an upstart inventor and id like to get in contact with you regarding the specifics of power generation.
sspence (author)  Calderick3 months ago
greentrust@gmail.com
ttucker103 months ago

couldn't you use a car alternator? I'm not being funny.. Wouldn't that work too?

sspence (author)  ttucker103 months ago
No, it would not. Car alternators have power robbing field coils and are designed to turn at several thousand rpm.
ttucker10 sspence3 months ago
OK thanks

this is all new to me but have been interested in going green for some time. I live in the mountains of North Carolina, so we have wind all the time. I am going camping for an undetermined amount of time. I bought a ten person, 3 room cabin tent so I would not be cramped for space. I have been researching several kinds of windmills and yours really caught my attention. most of the windmills I have looked at won't power much, but yours seems to have the power I need. I need something that will power a dorm frig and a microwave and also charge my laptop and cell phone. I am not really that mechanically inclined, so I will have to have someone help me. is there anyway you can send me step by step instructions and material list?

Sincerely,

Robert P.

sspence (author)  horsewhisper60433 months ago
If you need step by step with theory explanations, and a beginners class in electrical generation, I suggest Homebrew wind power http://goo.gl/kW2LM8
gpoli23 months ago
Hi,
I'm about to wind the coils and was wandering what lenght u used for the 2 strands of 14 gauge wire?
And how much should the centre spacing be? Or doesn't this affect the coil as long as it has 35 turns?
sspence (author)  gpoli23 months ago
on a 1x2x.5 magnet, each turn is about 7"
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