Picture of Build a Savonius VAWT to Make Electricity 2012 Update
Once upon a time, I wrote an instructable on this subject and it has changed my life.  As things have progressed very slowly, to some it may have appeared that I fell off the planet.  To those that know me, it has been a difficult and arduous but rewarding process.  Here , I would like to again share a Do It Yourself version of the turbine that I hope will also help change the world.  If this sounds idealistic, forgive me, I tend to be that way. :)

I want to thank everyone - over 100 commenters on my original project - for their input and knowledge as well as their questions that lead me further in my pursuit.  Thanks Guys!

I will try to take an approach on this project where I will give steps first and explanations of why following.  You will also be able to download, as I did on the original project, a pdf with the whole process.  Most of the document is the original with additional information that was not in the original.  http://www.spinpower.org/DIY/My_Savonius_DIY.php  (This is php to force the download instead of trying to open in your browser.)  My website is http://www.spinpower.org if that wasnt clear above.  I also have the following website name pointed to the same place http://www.smart-turbine.com .

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Broom3 years ago
OK, sorry if I've missed it, but why are you bothering to build a generator as part of the project? It's very difficult to even come close to the efficiency of manufactured motors for this purpose, I'd imagine.

If the point is "DIY!", I get it. But if you're advocating for more home wind-power to make everyone less dependent on the system, Reduce-Reuse-Recycle is the mantra that points towards grabbing an old motor from a junkyard.

Regardless, this is a great 'ible!
static Broom4 months ago

There are many places even, in the USA, where on can't go to the junkyard and find a used Permanent Magnet DC motor that's suitable for a practical duty cycle when used in a wind turbine. I understand there are issues as "cogging" that come up when using motors as generator or automotive alternators.

bhunter736 (author)  Broom3 years ago
Actually, the home built alternator is much more efficient at generating power. Turning a motor to generate power is opposite of its design and one of the biggest flaws in commercially designed small turbines. This is why I now have 9 international patents on the subject and a commercial venture forming for this turbine. The "old motor" is easier, but if you look at Farouns projects, he is still seeking 100 watts peak output. I can get that from my generator in a 9MPH breeze and over 1000 by the time wind speed hits 32MPH. The commercially built version of my turbine hits 1750 watts at 32MPH winds.

Having Resource Conservation Coordinator as my professional title I really appreciate the mantra and definitely share it. Its thinking outside the box and consideration for all possibilities before we give up that will help change things for the better. Keep it up.

PS - Thanks for the compliment. :)
OK, totally did not expect that home-built would exceed a motor for efficiency. Can you name a specific or two that make the reverse process more wasteful in motors? (BSEE here; just looking for a quick pointer, not a big explanation.)

bhunter736 (author)  Broom3 years ago
OK. Ill try to keep this short and simple.

A regular permanent magnet motor is designed to perform at a specific RPM and specific electrical frequency - house current. Typically the motor RPM rating is 600 or higher - there are exceptions. A vertical turbine may never go over 100 RPMs in its useful life, so you have to gear up, adding mechanical losses. Also, the wiring inside the motor as I mentioned is optimized for a particular electrical frequency or Hz which will rarely be attained as wind speed changes all of the time - changing the Hz as RPM changes. Also, the magnets used in a motor are complimentary to the need of the motor -as a motor- and are typically much too weak to be very useful in the other direction. In the case of a stepper motor you add severe cogging, (magnetic grabbyness <- not the technical definition), as well.

There's still a lot more than this, but I'm trying to keep it simple as you requested. :)
Thanks again!
Blast123452 years ago
This may be a dumb question to ask, but is the 1.75 kW figure referring to energy production per hour, day, month, or year?
ajohnson272 years ago
Hey Brad, hope things are going well for you. So I finally got back to my turbine project after it was destroyed in a storm last year. Something I didnt quite understand and revised this time was in your tutorial you use 16 magnets and 16 coils. If using 16 magnets and alternating north/south the 1st and 16th magnets will be configured with the same polarity. Additionally when wiring the stator into a 3 phase "Y", one phase will have 6 coils where the other 2 will have 5 each. Was this intended? I modified my current model to use 15 magnets and coils to avoid this, but I dont know if thats a good thing or not. Lastly, having it wired to a bridge rectifier, how would you suggest to measure the power generated? Is it required to provide a load while measuring, and if so what is your suggestion for a load? I finally have mine up again, but no wind today (literaly 0-1mph), so its not spinning yet. Just using my hand I can get about 55 rpm, and with no load the volt meter reads .06v on average. I am not sure what to expect or how to accurately measure, does that look about right? What would I see if one of the phases was not complete, like a break in the wire? Just a drop in voltage or a complete failure? Sorry for all of the questions, but I am really enjoying learning and anxious to understand my measurements. Tomorrows wind forecast is an average of 16mph, should be a good testing day.
Ok, so after I got the bridge rectifier wired right, and figured out what I'm testing, and today we have some wind, 12mph avg. With just a multimeter (no load) I am averaging 26v, and bursts up to 35v. Any better way to test this, and still looking for an answer on the 15/16 coils and magnets. Thanks!
dwleo3 years ago
Great instructable. Was seriously going to try it but those magnets that you bought (24 for $150) are now just under $500 for the same thing.
Gonna have to think about this a bit.
BudBump3 years ago
WHY can't I download a PDF copy after logging into my account?
bhunter736 (author)  BudBump3 years ago
You shouldn't even need to login for my primary PDF listed above. http://www.spinpower.org/DIY/My_Savonius_DIY.php
Thank you!
sarahbopp3 years ago
All together, about how much did this cost you to make?
bhunter736 (author)  sarahbopp3 years ago
The commercial development has been very expensive, the original prototype was about $700. The price of the magnets has gone up significantly, and would probably make it closer to $800 today.
I am completely out my element on this site and in this section. I was curious if you had given thought to how much a retail price would be if you successfully started your company?
ajohnson273 years ago

I wanted to thank you for taking the time and effort to share you ideas, especially in a way that helps facilitate people of any background to build one themselves. Thank You!

I have been interested and have read and learned for 3 years on wind turbines. The very first time I 'googled' wind turbines, it was with intention to build one of my own. However I quickly learned that the options and methods varied so widely that I had a lot to learn before I would make my choice for a build. Always in fear that I would begin purchasing and building only to result in failure due to lack of education and preparation. Always on the edge, and ready to dive in, I came across your instructable while browsing after my weekly newsletter update. Immediately i begain reading your website and instructable, researching the pro's and cons of a savonious, and understanding the practicality. I said outloud "I found my first Wind Turbine, this is it".

That was about 2 weeks ago, and in a few days I had my turbine up in the air. On a budget, my first mount failed quite quicklyl, but I was kind of expecting it. I thought maybe you would be interested in my progress so far, and have been posting videos to share with my out of town friends and family: http://www.youtube.com/watch?v=rQH8i5YGBQY

Again, I wanted say THANK YOU!
bhunter736 (author)  ajohnson273 years ago

Great video, and great build! :) I'm glad to help. Those magnets and wire are the most costly part of this build, but you know first hand how much energy you are collecting from simply trying to stop the turbine.

You are very welcome.

glad to see youve re-surfaced,and with my favorite instructable of all time,you inspired me years ago and hopefully will continue to do so
Michael_oz3 years ago
Hi Brad,

Where can I get a look at your patent, google was not my friend :(

I thought your rotor method is just like using a stepper motor as a generator, been done for many years??

bhunter736 (author)  Michael_oz3 years ago
Hi Michael,

A stepper motor would be like a distant cousin. What I have done here is very similar to a stepper motor in that we use permanent magnets and wire to generate power. 7 of the specifics in my patent pertain directly to autonomous adaptation for electrical pathways, voltage stabilization, rpm stabilization and output wattage maximizing output power based on wind condition and without adding any additional moving parts. All facets of the patent have design specifics to attain an optimum balance for these specifics to work properly. This is why the patent was filed with the option to remain hidden. Its kind of like the kernels secret recipe, we all know something similar but the magic is hard to reproduce. I'm sharing enough here to help a DIYer build a powerful and useful machine like the first one I built. Where it can go from there is only limited to the skills and imagination of the builder.

Beekeeper3 years ago

Two questions:
1) looking at your drawings you have the two pieces of opened out ducting or chimney facing in opposite directions and between the two there appears to be a two inch tube. This tube doesn't seem to be mentioned anywhere?

2) If one made a two-tier version with the top and bottom sections going in opposite directions, could one attach the magnets to the base of the top section and the coils to the top of the bottom section? In this way the magnets and coils would be passing each other at double the speed as in your existing model. Whether this would be more efficient I don't know. True there would need to be some way of having a rotating electrical connection, but that is done all the time.
bhunter736 (author)  Beekeeper3 years ago

1) There is no tube, the pipe sections support the structure once they are cemented in the wood.

2) This is a nice idea that was brought up many times when I published the first version several years ago. The problem is simple - We want to convert the force of the wind to electricity. Speed over the wire will have a direct relationship with the voltage as well as the mass of the wire having a relationship to Amperage. When you start factoring the added complexity of what you suggest, you may also realize that using wire half the gage and twice as long would also double the voltage for the same rotational speed. However, consider that voltage is like pressure and will actually play directly into the amount of force required to start the turbine spinning. These variables are all intertwined and are a very interesting set to play with as I have done for several years now.

2b) a rotating electrical connection will most likely require an electrical brush or some point of contact which will add to maintenance. Not out of the question, but I prefer to make a machine I can just look at for 20 or more years without needing to change brushes or service mechanical parts.
Thanks for your detailed reply. I see I can't re-invent the wheel! Just for a bit of fun I have a couple of bicycle wheels spinning around at the end of my drive which of course conveniently come with bearings. In one case the wheel is horizontal and I have three wind-catchers made from plastic pails cut in half vertically. Three seemed to work better than two.

re 1) OK, so what is that little circle in the middle of your drawing? I tried to add a picture but it wouldn't work but it is the same as your little icon on every one of your comments.

bhunter736 (author)  Beekeeper3 years ago
I was experimenting with various degrees of overlap and comparing the change in torque generated to rpm. There is a study done by Carnegie Mellon as well as Sandia Labs on the subject and I was experimenting and trying to understand their findings. My avatar is the same image, it just happens to be the very first time I drew it all out nicely and put it on instructables back in 2007, a project that started a new and very promising tangent in my life; The image is one of my favorites and I think would make a great crop circle/pattern. :)
BaiCam3 years ago
email on website does not work?
bhunter736 (author)  BaiCam3 years ago
Which email? brad@spinpower.org?

This is the email that is used after filling the form in.
bhunter736 (author)  BaiCam3 years ago
Ooops. Where did you see that email, I need to update the page. The email should be info@smart-turbine.com. Thanks for the eyes! :)
It is automatically generated when the Investors form is filled in.
bhunter736 (author)  BaiCam3 years ago
Thank you. I updated that page to log into a database instead of triggering email. - Brad
Great, thanks.
rhackenb3 years ago
Nice tutorial. It looks like a solid design.

I have several questions:

1. Do you have a good photo of the entire wind turbine so that you can see how the stator coils are mounted? How close are the coils to the magnets?

2. What should be the inside diameter of the coils? i guess this would be the distance of the two screws around which the wire winds.

3. Do you have a video of the turbine in action?

4. What is the difference between magnetic wire and regular wire of the same gauge? Can regular electronic hookup wire be substituted?
bhunter736 (author)  rhackenb3 years ago

1. I don't think any of the overall photos would do a better job than the one already included in the alternator step. Coils are as close to the magnets as you can get them without making any contact during rotation. You have to leave some extra space for turbulent or storm winds that may twist and rock the frame.

2. Inside diameter should be as small as you can get it. And you are correct about the two screws. :)

3. I will try to find some video of the turbine, most of what I have now is the commercial build and there are some significant differences, however this project was the first generation.

4. Magnet wire is solid core wire with an enamel coating that is very thin vs a PVC or similar sheath that is considerably thicker. Hookup wire can be substituted if it is solid core, like individual lines from inside of Cat5.
rickg13 years ago
Could you add additional coil magnet combination to the other tiers? Wouldn't this triple the output? or would it be too much resistance for the unit to spin?
bhunter736 (author)  rickg13 years ago
Your second thought is more on track. There is only so much force in the surface area of the turbine. Adding too much work will actually lose power. The starting point in this project is good for all kinds of wind locations. If you have a particularly high wind environment, you could add coils and magnets to increase the draw from that available force.
bhunter736 (author) 3 years ago
In order to answer a question of power curve, the manufactured prototype was used to supply the data on a specifications sheet that I have attached here. The curve is based on yearly output. My hand built project had a peak of about 1150 watts and the manufactured model is 1750 watts, so you will probably see an output level closer to my original hand built machine.
bhunter736 (author) 3 years ago
If anyone is going to be in the San Francisco area this weekend, I will be in the DIY area of the Earth Day gathering at Civic Center. I will have the manufactured prototype with me for -show and tell- as well as handing out information leading to this instructable and the PDF of the project.
I live in San Francisco. What times will you be there? Saturday and Sunday?
bhunter736 (author)  alcurb3 years ago
Just Sunday - The whole event.
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