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!

## Step 1: Build the Magnet Disks

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

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

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

<p>Good job on the generator!</p><p>Could you elaborate a bit on the mechanics, e.g. how turbine rotates around vertical axis, are you taking any measures against cable twist, are you offsetting your turbine in strong wind in any way (mechanically or other)?</p><p>Thanks MIke</p>
I'm using harley wheel bearing on the vertical part. I manually untwist on occasion, but it hasn't been a big issue. there is an offset tail to point the turbine into the wind,and turn it out of the wind in winds above 30 mph. All that was beyond the scope of this instructable, but is documented in Dan Fink and Dan Bartmann's book.
<p>Slipring</p>
Thank you for the explanations and pointers ... good harvest ;-)
<p>Have a question? How do you run several wind generators at the same time to feed one battery bank without the charge controllers canceling each other out or can you run several generators in series some how and go through the one controller? I do not see how anybody goes off grid and runs their whole home using just one wind generator, even this 1000 w PMA will not put 1000 watts out unless the wind is blowing hard and constant all the time running it at full speed. It probably will only put out around 150- 350 watts bouncing up and down as the wind speed changes all day long. Can't keep a battery bank charged up and run your home on that little bit of power. Just wondering.</p>
<p>query</p><p>Each coil produces 4 volts</p><p> 3 per phase connected in series give the 12 volts</p><p>it is right</p>
<p>Really good source of energy ! Respect for you man ! :)</p>
<p>Hi nice project and impressed you made it all yourself. Was wondering would it be any easier and/or more cost effective to use a bike wheel motor? I can get a 1000w version for &pound;150 in the UK. You say this project costs \$1000 - \$1500. How much of the time / cost is spent on the motor? </p>
<p>I was wondering the exact same thing too. Usually DIY (and especially non machined) things like this are extremely inefficient compared to a pre-made ones. I'd be very surprised if he got anywhere near 1000w. Does he list any electrical figures anywhere?</p><p>AFAIK you are better off getting a slower but more bulky generator rather than a small one that spins too easily and fast. So a bike one would not be the best.</p>
I have seen a commercial wind turbine that uses bike motors and claims to be very efficient. Cost about &pound;1000 and made 1000w watt max. <br><br>I have read that such motors are ideal for the job. No time to find links. Google it my friend.<br><br>Not sure about his home made one being inefficient. It looks good to me. It's only magnets and coils. Select quality ones. The bearings will only add a very small amount of extra drag, even low quality ones. My main issue with making your own is the effort and it's not much cheaper. Fun to make your own though if you like doing that. We are always going to depend on industry others to make the wires and magnets!
<p>you be-d wrong!... this can put rated watts out easily &amp; can be MORE affordable &amp; can last for years!. Do the research! Why are you wasting time on Inscrutable just go buy one!</p>
Hi John. Google it. Apparently they are perfect for the job. There's even some commercial home wind turbines using them that give 1000w in good wind. <br><br>Maybe sspence is not interested for other reasons, IDK, maybe it's more green if you make it entirely yourself. Nice work though designing and building it all yourself, must be pretty satisfying.
<p>Interesting. Any chance you could link the &pound;150 / 1000w one you meantion? Thanks.</p>
About half was spent on the alternator, the other half on the tower. I'm not interested in bike wheel motors.
Thanks for the info. Half/half makes sense. I guess you must find it more interesting to make it all yourself? I have heard the bike wheel motors are perfect for the job. I will do some more research. Have a nice day.
<p>Yes for sure not enough info to bad looks like a fun build</p>
Hi SS<br>Which grade magnet is better N-32;50;52
<p>52 is stronger.</p>
<p>&quot;Is our Children Learning?&quot;(infamous quote from G.Bush) I realize that many of the readers here may not have access to friends or library but those that DO have access; go to the library, take a friend or family member/neighbour that has attended a high school or college physics class or has professional experience. At the library, ask the librarian for books on basic electricity and magnetism. The principles outlined there may help you, with help from your partner, understand what is going on with the DIY generator and help you with other projects not to mention the realization that the public library is good for stuff besides free internet ...and you could even bring your new found understanding back here !</p>
<p>Height of coil can increase magnet height.</p>
coil height (depth) has nothing to do with magnet height. only the gap between the magnet and the coil is important. keep is as small as possible without interference. a 1&quot; wide x 2&quot; long x 1/2&quot; deep magnet needs a coil that has a 1&quot; x 2&quot; whole in the center so that it only swipes one side of the coil at a time. The thicker (depth) the coil, the less flux on the further side of the coil. so pack them tight and thin as possible.
<p>Inside diameter of coil should be greater or less than magnet,and height of coil can increase mag height.</p>
<p>The magnet should just fit the open center of the coil.</p>
<p>ok </p><p> if i want to produce 2kv with 9coils and 18 magnets which guage is better and number of turns required.<br><br><br>thank q</p>
<p>72 turns of dual 12awg for 24v, 83a (2000w) depending on wind and blades. see <a href="http://www.green-trust.org/windpowercalc/" rel="nofollow">http://www.green-trust.org/windpowercalc/</a></p>
<p>Hello,Thank you for posting this,but I would like to see more detail,for instance what is the diameter of the 12 volt coils and more detail about the mount and how much Epoxy did you use and does it matter what type,can you add these things to your post.<br>Thank you<br>Bob</p>
<p>IIRC, it was about a quart of epoxy. </p>
I have 18 pieces of N50 magnets with the sizes 48mm&times;19mm&times;9.8mm which I want to use in making my homemade wind turbine. But I don't know the amount of power I will get when it is done. <br><br>But I'm sure I will gain experience as time goes on!
<p>the number of turns per coil decides the output voltage. The gauge of the wire determines how much current you can pull, providing your blasdes can catch enough wind to turn at load.</p>
<p>if i want produce 2kv with 14 guage how many turns required for each coil ,</p><p>and 16guage how many turns required.(total 9 coils).</p>
<p>HI ss</p><p> iam doing 2kv turbine ,shell i use 50mm*25mm*10mm neodymium magnets ,is enough for 2kv watts producing ,,and which grade is best for turbine</p><p> (i mean N32,N42,N50,N52 ......like ).</p><p>if any changes should do or not.</p><p>thanku</p>
Can your coils handle that much current? The higher the grade magnet, the more magnetic flux.
<p>Me too</p>
I know that every coil has two output wire. So how did you joined three coils with six output wires together to get just one output wire, please?
series, so there are two wires. one comes out of the machine, the other connects to the common of each of the other two series sets.
<p>Do you have a materials list laying around?</p>
<p>Just wonderful. Your whole profile and ideas and ideals.</p>
<p>what kind of resin do you use to cover the stator and rotor?</p>
any fiberglass resin will work.
<p>hi sir please replay all of my 4 question because I am doing this as my college project.</p><p> 1. This my rough diagram arrangement of mag rotor,it is correct or any changes take place.(below)</p><p>2.i want to wind 14# 3parallel wires 35 turns to produce 1500w and how many rpms should rotate to get 1.5kv, can u estimate how many amps can I get.</p><p>3.and it can rotate 24hours, are any damage occurs.</p><p>4.i am buying 12v luminous inverter with 1000w*2batter ,how much time will take full the charging.</p><p>Please reply all of my 4questions because I am doing this as my college project. </p><p> Thanks,.</p>
<p>The request looks a bit wired: &quot;Sir ... answer my questions!&quot; </p><p>As far as I know student projects have to be designed and solved by the students not by asking other people how to solve ;)</p>
<p>thank q ,</p><p> which type of inverter and battery i should use for storing 1500watts</p>
1500 watts is a instantaneous amount of power. Batteries store amp hours or watt hours. Neither has anything to do with an inverter. clarify your question.
<p>OK ,IF I GET 1500W AND 125AMPS FOR 1HOUR WHICH TYPE OF INVERTER AND BATTERY I SHOULD USE.</p>
<p>Depends on your daily loads, and how much wind you get daily. Aren't they teaching you this in college? It's basic high school physics.</p>
<p>hi sir ,</p><p> i forgot to say we are implementing only your turbine planes,and we are not doing wind turbine (only we are doing magnet coil rotor),</p><p> please answer IF I GET 1500W AND 125AMPS FOR 1HOUR WHICH TYPE OF INVERTER AND BATTERY I SHOULD USE.</p>
<p>You have not specified your loads. What wattage are they, how many hours do they run, how much run time do you need when the alternator isn't running . This is what determines battery and inverter, not the alternator.</p>
1. correct<br>2. 650 rpm, 1500w / 12v = 125 amps, if you have 12' blades at 15mph, or 4' blades at 30 mph.<br>3. 24 hour operation only affects bearing life.<br>4. battery charge time is dependent on how low the batteries get (amp hours out), and the amount of charging available, (amp hours in). With wind, there's no way to forecast your daily ah production, as wind is too variable.
<p>How did you get 24 volts? Those magnets are about .38 teslas, and the coils are about 1 inch by 2 inch, just by my eyeballing it. </p><p>What frequency/rpm do you use as a basis?</p>