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Build a Savonius VAWT to Make Electricity 2012 Update

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Picture of Build a Savonius VAWT to Make Electricity 2012 Update
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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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Step 1: Materials Tools and Safety

Picture of Materials Tools and Safety
--Materials--:

Specialty Item prices are what I paid and may change

Magnet wire – 780 feet of 24 AWG  or twelve 65 foot spools of 24 AWG    $22
http://www.bulkwire.com/product.asp?ProdID=7615&added=1
16 Neodymium magnets - 1”x2”x ½”  (I had to order 24 for the $150 price)   $150
http://www.forcefieldmagnets.com/catalog/
Rectifiers (one full bridge for each phase – I recommend 3)      $6 ea
http://www.forcefieldmagnets.com/catalog/
Plexiglass – ¼” thick sheet about 25”x7”        $Free
Scrap at city or school maintenance base
Skate Bearings (you only need 2)         $3 ea

Home Improvement Stores
Galvanized sheet metal squares 2”x2.5”x about 18 or 20 gage
Glue – not cyanoacrylate or any others with harsh solvents, but must be
very strong and weather resistant I used Gorilla Glue and Liquid Nails
small projects clear indoor outdoor as well as Liquid nails in a caulk gun
Thread Lock (not the permanent variety, but high strength for sure)
Extension cord – sacrificed for delivering power from turbine to charging location
Screws – must be weather resistant (I use the 2” plated drywall screws, they are easy)
Large washers – used with the above screws for attaching coils to VAWT platform
Pressure treated wood for base of structure (32”x32” area for base)
Rounds (24” diameter, 2 for a single tier or 3 for a two tier)
Stove Pipe (2x 6” diameter for a single tier or 4 for a two tier all 36” length)
Pipe Nipples (3x 36” for single tier or 5 for a two tier)
Pipe Nipples (2x 3” for top extension)
Pipe Couplers (2 for single tier or 4 for two tier)
Pipe Elbows (2)
Bolts (to fit in bearing about 3 or 4 inches long, get several but you only need 2)
Nuts (for bolts, get at least 6 to allow for adjustments – its cheaper than a second trip to the store)
Washers (Fender to fit over the bolts, get at least 6)
Weather Treatment – Polyurethane or outdoor grade paint
Ball Bearing (you may find that buying a childs magnet building kit at a Target is cheapest, you only need one, size not critical but about 1/4” diameter or bigger is good)
Guy Wires and accessories (you will have to tie this to the ground so it doesn't blow over or wiggle)

Separate from the power generator is the rest of the power plant:

Batteries to store and buffer power
Charge Controller for batteries
Inverter to make battery power 110 VAC
Transfer Switch to run Inverter power to a house


--Tools--:

Power Tools:
Router with narrow plunge bit to cut a channel or similar rotary cutting tool
Hand Planer or Belt Sander to true up the rounds
Drill for driving screws and the occasional hole
Drill bits, standard and one paddle style that is the diameter of your bearing
Hole Saw (this is to make a jig, size not critical but should be 2” or bigger)

Multimeter
Soldering Iron, Gun or Torch and solder

Welder - optional for heavy duty build which also requires a length of steel and 1/4x20 screws, a tap to match and some steel squares, about $15 of additional materials around here.

Standard Tools:
Screw Driver
Hand Saw
Wire Cutters
Snips for cutting galvanize squares
Strap or Rope to tie unit together while glue dries (you could weight it down)
Clamp not necessary but will make some things easier
Compass (to find center of rounds)
Pencil
Markers (red and black preferred)
Measuring Tape
T-Square or other Straight Edge
Hammer (you never know with this one, something may need persuading)
Vise Grips (for steel upgrade, used to hold tap if you don't have a tap and die set)

--Safety--:

This is a DIY project, as always, you take responsibility for your choices and actions.  This is presented for you to learn from and potentially mimic in order to produce a working electricity generating wind turbine.  Also, the power generated is dangerous.  Please maintain a high level of respect for this machine.  My current revision will directly light a 60 watt light bulb in a 6MPH gust of ...  Oh wait, thats not so much a gust as it is a breeze.  The power output is scary.  Treat it like power from a wall outlet.

Always wear safety glasses, ear protection and take all precautions when working with tools and raw materials.

Good Luck!

Step 2: What to do first...

Picture of What to do first...
In short, make 3 wooden circles that will be the top, bottom and "hip" of the turbine.

I used plywood for this revision, the thick flooring grade stuff.  One 4x8 sheet was more than enough.  Using my Rotozip and a plexiglass guide that I made, I was able to make very nice and "true" circles.


Step 3: After the circles... Step 2

Picture of After the circles...  Step 2
Mark half circles that approach but do not overlap the edge of the circles.  They need to align so that they form an "S" shape.  Trace the half circle marks with a plunge router or Rotozip but limit the depth to about 1/2 inch.  This will create a channel for the stove pipe or "sails" to set into.


Step 4: Step 3 ... Repeat Step 2 .. but not really

This may be complicated to show here, but imagine the top circle the shape of the groove is an "S" and the bottom which will be facing the top is the mirror image of an "S".  The middle circle will be a mirror of an "S" on one side and an "S" on the other but also set at 90 degrees off from each other to make a squiggly + sign if you imagine it as transparent material.  This is better covered in the PDF.

Step 5: Step 4 .. Dry fit

Picture of Step 4 .. Dry fit
Open the stove pipe and flex it so that it wants to be more like 1/2 of a 1ft circle.  When the metal is more relaxed to the right shape, you can dry fit it into the grooves you cut in the circles.  The notch in the photo below is only there for the purpose of illustrating how the sail penetrates the circles, you do not need to mimic this feature.

If the dry fit is good and you are able to apply the top and "hip" circles at the same time, you will want to verify the orientation of the bottom and "hip" next.  If all is good and you have all of your orientations correct, it's time to glue.

Step 6: Step 5 Glue ... If there is any doubt, repeat step 4

Fill the channel of either the top or bottom circle, not both, with construction adhesive.  Insert the stove pipe.  Find the mirror channel on the "hip" circle and fill it with construction adhesive and position it on the sails so that you have 1/2 of the rotor assembly together with the wet glue.  Strap it and leave it to dry for at least 24 hours.  You will be sorry if you try to do the second section and the first pulls apart, it's messy and ruins the quality of the bonding.  This step uses a thick bead of glue which will take extra time to dry.

Step 7: Step 6 ... Glue the second section

Same as step 5 with the remaining section....  Wait another day for glue to dry.

Step 8: Step 7 ... Reinforcements

Picture of Step 7 ... Reinforcements
Drive screws through the metal and in to the wood circles in two locations on the connection point of each sail, a total of 16 screws.  1 inch screws are fine.  The outer most edge, about 1/2 inch from the metal vertical edge is the most important point.  At higher RPM, and high wind, the stresses at this location can start to peel the steel out of the channel.  This extra step will help ensure your turbine can handle high speed winds and strong sudden gusts.

Step 9: Step 8 ... Look at what you have done :)

Picture of Step 8 ...  Look at what you have done :)
Take a step back and be proud you have come this far.  Then, paint, paint, paint.  Primer, UV sealant, the works.  I can not emphasize enough how important this is for the turbines longevity.  It may feel like a lot right now, but its much easier than having to bring the turbine in from the yard or wherever it is and strip it, re-finish and re-install it.  Get it protected now and put that problem off for years.  From my experience, I've painted mine several colors.  Start with white.  Camo, grassy, clouds and other fun stuff goes over white just fine.  So again, start with white.

Step 10: Step 9 ... if you havent painted, go back to 8 and paint

Picture of Step 9 ... if you havent painted, go back to 8 and paint
Decide which end will be the bottom.  This is where you will need to mark at even spacing, 16 tick marks for the magnet positions.  I found that gluing the magnets on with construction adhesive was a lot easier if I put a screw in the circle first, directly at the measurement marks.  The magnet will stay at the location as it is attracted to the screw and this makes for easier gluing.

Caution:  These magnets are tough.  Be careful.

Mark the magnets with red and black or something so you know which way is which.  It doesn't matter which is North or South, so I will refer to them as A and B.  Just mark them while they are stacked so they are consistent as you glue them.  Attach an "A" at every other measure mark and let them dry for no less than 24 hours.  Next wearing thick gloves, attach a "B" at every remaining measure mark.  Extra caution for this step, the blood blister I got through my leather work gloves was very painful.  Wait another 24 hours and add a bead of construction adhesive along the edge of each magnet.  Wait another 24 hours and add paint to the magnets.  Seal this stuff good.



Step 11: Step 10 ... a winding jig

Picture of Step 10 ... a winding jig
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Make some kind of winding jig.  I used a 5 inch circle saw to cut two circles in plexiglass.  You can see the result here.  I use them with a bolt and several nuts to create the jig.  I can then load the jig in a drill for fast winding.  Once I have a wound coil in the jig, I can loosen the nut to remove the coil.

Wrap with electrical tape immediately and set aside.  Repeat the coil making process 16 times with about 50 to 65 feet of coil depending on AWG of 24 or 26.

Step 12: Make 16 coil mounts ...

Picture of Make 16 coil mounts ...
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This can be simple or ... not.  What it does have to be is non magnetic.  Wood or plastic is a good choice here.  Whatever platform your turbine will rotate above needs to support the coil holders nicely.  I ended up with a simple 2x4 block that I mount to the platform with stainless steel screws.  The minimal magnetic properties of the stainless are perfectly acceptable.  You can also use plexiglass or left over plywood as shown.

Step 13: Be creative and build a frame

Picture of Be creative and build a frame
You will need a simple frame to hold everything.  You will also need to support the rotor with some type of bearing.  See my diagram below for an early prototype arrangement that I used for experimenting.


Step 14: Connecting the wire coils ...

Picture of Connecting the wire coils ...
This is the step that gets people into the most trouble...  it doesn't have to be complicated but it just doesn't seem to travel very well.  All coils should be made the same way and all common fronts should face the same way (toward the center of the rotor or all away from the center of the rotor).  When mounted properly, this allows for easy single phase wiring as follows:

Edge of coil A to edge of coil B - Center of coil B to center of coil C - Edge of coil C to edge of coil D - Center of coil D to center of coil E, etc...

Leave only the very first and very last wire open or un-connected, this will be where you hook up a diode or rectifier.

NOTE:  DO NOT MAKE THESE CONNECTIONS WHILE THE ROTOR IS SPINNING, THERE IS POTENTIAL FOR ELECTRIC SHOCK.

Step 15: Whats a diode or rectifier

In overly simple terms, a diode is a "one way gate" for electrons.  A set of 4 diodes is like a lighted intersection that organizes all of the cars so that the flow of traffic is all diverted on to a one way street.  This effect is turning AC into DC current.  The DC current can be routed through a charge controller and into a battery for storage.

Step 16: Thats it for the basic build...

Picture of Thats it for the basic build...
again, you can download the PDF for a lot more detail and research information.  You can visit my website for information about the commercial version of the turbine.  I hope you find this collection of information helpful.

Sincerely,

Brad

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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 Broom3 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.)

Thanks!
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!
Blast123451 year 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
Brad,

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
Hi,

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.

Brad
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??

Michael
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.

Brad
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.
Beekeeper
bhunter736 (author)  Beekeeper3 years ago
Hi,

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.

Cheers
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?
cgu@smart-turbine.com

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
Hi,

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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