7 Foot Axial Flux Wind Turbine

This instructable documents the process of my single rotor wind turbine. It is built with inspiration from Hugh Piggot and the folks at Otherpower.com. This is my first attempt at building a wind turbine, and I will try to include the mistakes I've made along the way so that other first-time builders can avoid them! Since this entire project has a budget of just about $1000, it is meant to be able to be completed by both newcomers to wind energy as well as those who don't have a lot of money to throw around. I also tried to use as much recycled material as possible, so a large portion of this turbine is made from a junked car and metal that was going to be thrown out by fabricators.

When I first began this project I had a decent grasp of electricity and electronics, which was helpful. I knew hardly anything about wind turbine design, but picked it up quickly with the use of several books and websites.

The books and works that have been most influential in the building of this wind turbine include:
-Windpower Workshop by Hugh Piggot
-Windpower by Paul Gipe
-Arc Welding Instructions for the Beginner by The James F. Lincoln Arc Welding Foundation
-Otherpower.com as well as many helpful individuals on the Otherpower forums

If you want to know more about electricity or electronics, the book Teaching Yourself Electricity and Electronics by Stan Gibilisco is a great learning book and valuable resource to have around.

Here is a video of the final project.

(The whole thing about the modern day Don Quixote... yeah, I don't think it's right either.)

Step 1: Deciding on Size

Since this is my first wind project, I decided to work on something that is a bit easier to construct than a high-output "dual rotor" design. I also didn't have a lot of metal fabrication shops available to me, so I was looking for something that required little fabrication.

A Volvo brake rotor has become popular among homebrew windpower enthusiasts because of its wide availability and its relative ease of modification. Volvos have a reputation for being long lasting and their rotors are not much different. A trip to the junkyard landed me with a $20 Volvo 340 strut (rotor, spring, and everything).

A single rotor design only has one set of magnets that spin in front of a stator coil. This makes construction easier and less dangerous, since you don't have to use "jacking screws" to bring together two magnetic disks. This is dangerous because if you slip, you could very well break your hand or finger. With a single rotor design, there is much less chance of this.

One thing that many people don't realize about wind turbines is that the blades of a particular turbine are matched to its generator. This is all based on what is called "Tip Speed Ratio" or TSR. By matching the correct blade diameter to your generator, you ensure that the turbine will start generating at a certain wind speed. By having the right size blades and generator, the correct RPM and torque will be produced to generate the maximum amount of power safely (that is without overheating or over-speeding the turbine). Matching the blades to the generator is a very important aspect of designing your windmill, and many other aspects of the machine are based on the blade diameter.

For this particular design the blade diameter should be around 7 feet.

Comments

[broken board]

G, DAY MATE

THAT IS FANTASTIC A JOB WELL DONE.

UM I PROB MISSED TI BUT HOW MUCH POWER DOES YOUR BABY PUT OUT.

I WAS GOING TO MAKE THE oops sory about the caps.
1000w turbine that is also on instructable but now im gunna make yours.

i dont have the space to place it so high in the air but im sure ill find a way to secure it to the top of our roof securely and safely

cheers bud

[sajoma62]

i met half of the volts

[sajoma62]

i want it to make the same wind turbine project,but i have a question ? if want it a 12v stator you said you had to purchase a 24v stator but in the pitcher it shows a 12v stator . i want it to know if a single 12 magnet rotor with a 12 v stator then it will only produce in low winds half of the watts. is that the reason you had to use a 24v.

[sgray11]

ive made a 9 coil 12 magnet stator an axel with the wind at 15 miles what will it produce i thought it was an AC output to a refractor so does it hook into the inverter from there an what kind of inverter do i need my refractor is an 80 amp is that right thing to use

[kbooth23]

Hey im loving this instructable, the wind turbine at my college got me interested in building my own. I thought this looked very do-able until i got to this step. I was wondering how much the controller and other parts in this step costed, and if it was difficult to assemble them all?

[brokengun]

I can't remember exactly what I paid for them. I think it was in the range of $120 each. I bought two, but only ended up using one as the charge controller. I used a bridge rectifier and a schottky diode to rectify the three phase power coming off the turbine. The controllers weren't hard to hookup the manual that comes with them is pretty good. There isn't any assembly required, just wiring the wind turbine up. I think I had to change the position of a jumper and that's about it, there are small potentiometers to change when the dump load is turned on (by checking the battery voltage).

I've really gotta update this thing though. Currently the turbine is down for repairs, a weak spot just above the weld on the tail's hinge pin gave out. I plan on redoing it almost entirely at some point but college has been keeping me busy.

If you've got any more questions, feel free to ask. One thing I can definitely say though is if you don't want to be constantly maintaining the machine make sure you don't cut corners. Do it right, or do it twice.... sometimes you gotta learn the hard way, eh? Best of luck.

[bertzie]

So wait, do you spin the magnets or the wire coil?

[megapix]

You spin the magnets. That makes it easier to connect to the coils, since they are stationary.

[ThreeWestCreative]

Excellent instructable! I'm thinking of building one of these for my home build project. But I was wondering, it would seem possible one could use the core technology (i.e. the magnet and coil assembly) and arrange for other ways to make it spin and generate electricity, no?  I was thinking, could I build that part and say use water power to spin it and make it generate electricity? Or find some other creative way to spin it.  :)  Thanks.

[brokengun]

 Sure, people build homebrew permanent magnet generators all the time for various applications. Wind, hydro, steam, human power, whatever. Just make sure when you wind the coils to get the right gauge wire and the correct number of turns. This can take a bit of experimenting sometimes, but you can also reference a lot of material online. 

Be sure to show us what you end up building, good luck!

[ThreeWestCreative]

That's great to know! Thanks. :) I'll be sure to document it and let you know. I will most likely work on something like this alone and don't think I'd be able to handle the pole creation and standing part alone but I could use this same technology for ground level electricity generation.

[mahesh.ganpate]

va....v very nice please send deatails images and drawing for genereter rating details i m starting a new wind turbine 1 kw manufacturing by home made . then so pls help

[brokengun]

 If you would really like more details plans for the generator I would suggest visiting Hugh Piggot's website and purchasing his book "A wind turbine recipe book". It's full of detailed plans and specs. 
 www.scoraigwind.com/books/books.htm

If you've got any specific questions I can do my best to answer them, if not the guys at www.fieldlines.com can probably help fill in any gaps. 

[mahesh.ganpate]

thanks , for u r sugess but we wont to 1kw genereter making the basicaliy rating of genereter  and  iwas perchasing this wec book but there not specifiy ingenereter rating ditails and wave deatials . i thk u r sugess me  .genereter details . india  here ueing the matric system . but book in site all dimanstion mph inch etc there  .

[brokengun]

 There are both metric and standard (english units) versions of the book available on that site. 

I think you want a more in depth analysis of the generator. Most homebrew wind power folks won't get that in depth. Basically Hugh's book would outline which generator plans seem to work best partly through trial and error. 

I think to get the kind of detail you want, you might consider a different book with more mathematics. However that book might also depend on if you are making an axial flux or radial flux generator. 

[mahesh.ganpate]

tx brokengun,

 
  i have agree with u u r coment  i have making  for axial flux genereter. but i don't know  which parameter using for generotor making,   only 30 mtr tower bearing ,gue rope , tail van avalable  here  but  genertor details not avalable

[brokengun]

 I guess I am confused as to what parameter you want. The book I recommended specifies wire size, number of turns and the physical dimensions of the coils and the casting. Basically everything is there. There is more information not included such as how much power that stator can handle but this can be roughly calculated depending on the resin used. 

The wiring of the coils is basically a matter of your application and preference (eg. star, wye, delta). 

[mahesh.ganpate]

how much price sir , book parchasing ,im not parchasised book

[mikeyeez]

Great job man bright future ahead.

[spylock]

You can buy a 400 watt wind turbine for about  $600.00 from the Sportsman's Guide,of course youve got to build or buy a tower,Theirs is 30' and about the same cost is about the same cost.

[brokengun]

 The one in the Sportsman's Guide looks like an Air-X brand generator, although it doesn't say the brand on their site. The rotor diameter of that turbine is slightly smaller than mine. Also, I have heard a lot of complaints about the noise generated by the turbine's blades. 

Other than that I don't know much about that turbine in particular. I've seen a few around. It looks like there tower setup costs $650 as well as the generator. Don't forget the controls, wire, batteries, concrete, etc you might need. 

I will say it is definitely less work! 

[spylock]

Yea,I just figured Id through that out there,the tower they sell in my opinion is kinda over priced.Also I was going to make my own useing a RV generator,and use the old control panel and stuff out of the RV Im scrapping what would be your thoughts on that?

[brokengun]

Do you mean the alternator that is hooked up to the RV's engine or a separate generator that produces electricity for the RV?

Car alternators charge at a very high RPM, much higher than most wind turbines so reaching charging RPM can be difficult or require gearing of some kind. 

Many people rewind the stator coils in an alternator with thinner wires to achieve higher voltages at lower RPM. It's a project and there is some figuring involved depending on the dimensions of the alternator and what power output you want from the thing. 

[spylock]

Yes,They call them altenators now,but this is an old RV and its actually a generator,I was going to do a small diam. pully at the blades and run a belt to get some higher RPMs at the generator ,and use the old breaker box,charge control and other stuff less the wire and recepticles.I figured Id run it to three deep cycle batteries,I just want to try something that will take care of my bedroom,computer,small lamp,ex. for when we lose power,sorry for the bad spelling by the way.

[Blackice504]

its a good and clean build but is this wind mill too heavy? i was thinking of making it out of fiber glass and really light weight stuff for the wind turbine.

[brokengun]

The machine is quite heavy, yes. However part of this is out of necessity. The rotor which is made of steel should be made from some ferrous material. A ferrous material is helpful for the efficiency of this alternator. I think it has to do with improving flux and essentially turning the entire rotor into a big magnet. However the back pieces could be made some something else I guess. There is a lot of stress on those part though. The bearing and nacelle put up with a lot of bad weather and harsh wind so I would rather have something with some heft. The other place to save weight would be with the tail. As far as that goes, I don't think you would save much weight compared with what I did. The electrical tubing used was very lightweight and the 1/8 inch stainless steel that the vane was cut out of is also pretty light. If you do end up making some of the pieces shown here out of fiberglass, I would like to hear how they hold up.

[Blackice504]

love the tower install great job

[brokengun]

Basically yeah... we had to expand on the 10 inch rotor to make it fit the stator coil that I ordered. However if you're good you can wind your own stator to fit a 10 inch diameter brake rotor. I'm sure a lot of different brake rotors have been successfully (or could be successfully) used like this.

[0087adam]

Is that a weedeater with a saw blade on it!? (in the background)

[brokengun]

Yeah basically. It's for clearing woody plants and stuff. We live in the woods.

[0087adam]

That looks really professional...

[0087adam]

would any old brake rotor work for this?

[oddelyodd]

great project I think it is a good Instructable and if you can send me the schematic and firmware for the controller with the lcd it looks very cool to make for projects like this one

[brokengun]

I didn't end up completing much of the controller at all. Really all I had was a voltage divider circuit to read 0-12 volts and a temperature sensor that worked on the LCD. I tried to find what little code I did have but I just moved to a new computer and apparently the old stuff is nowhere to be found. If I do locate it I'll send it though.

I used this LCD: http://moderndevice.com/LCD.shtml I would recommend it. I wouldn't recommend their arduinos.... I bought two and couldn't get either of them to work, maybe it's just me.

[oddelyodd]

that's OK but thanks though

[ironforger33]

Great instructable. Gotta love the name too.

[1234Becka]

Thanks for the info on your wind turbine and the list of books you got a lot of your info from. On most of the wind turbine "how to" no one gets to the part of the type of wires to run from the wind turbine to the batteries. I heard the wires and batteries is what cost the most. How far is your wind turbine from your house, and where are you setting up your batteries? Great job on you project and getting it set up!!

[brokengun]

I don't think the wires cost the most but then again I guess that depends on how far you want to run it. I used 3 conductor 6 gauge copper wire, which is pretty expensive stuff... Looking around online it looks like it's in excess of $1 per foot (probably much more for 3 conductor). I lucked out and got mine for free, there were lots of freebies in this project. I also only had to run it down the length of the tower to the box where the battery is. Keep in mine though, that my generator is a 12 volt one and thus requires thicker wires for lower resistance. Most people who would be doing a DIY wind turbine to supplement their house use a higher voltage which requires thinner wire. This is overall a good idea and I would recommend it as it will definitely save you money. Where the money really comes in is the tower, it's hard to get a good, solid tower solution for a good price. A lot of people tend to forget how expensive it may be.

[whiterabbot]

I would like to build a wind turbine on my uncle's property. He has two acres but there are houses close by too. I was wondering if anyone knows if what the stipulations are for putting up a wind turbine?

[brokengun]

They vary depending on your area. I needed to get a building permit and such but it would've made a difference if I was a certain boundary of a city. I would suggest calling up your town office and asking what the maximum size tower they allow to be put up. Also remember to get a good clear spot or a high tower to get the best wind possible.