How I built an electricity producing wind turbine

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Several years ago I bought some remote property in Arizona. I am an astronomer and wanted a place to practice my hobby far away from the terrible light pollution found near cities of any real size. I found a great piece of property. The problem is, it's so remote that there is no electric service available. That's not really a problem. No electricity equals no light pollution. However, it would be nice to have at least a little electricity, since so much of life in the 21st century is dependent on it.

One thing I noticed right away about my property is that most of the time, the wind is blowing. Almost from the moment I bought it, I had the idea of putting up a wind turbine and making some electricity, and later adding some solar panels. This is the story of how I did it. Not with an expensive, store-bought turbine, but with a home-built one that cost hardly anything. If you have some fabricating skills and some electronic know-how, you can build one too.

More details on this project and my other alternative energy projects including my home-built solar panels, and my home-built biomass gasifier can be found on my web site.

 

Step 1Acquiring a generator

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I started by Googling for information on home-built wind turbines. There are a lot of them out there in an amazing variety of designs and complexities. All of them had five things in common though:

1. A generator
2. Blades
3. A mounting that keeps it turned into the wind
4. A tower to get it up into the wind
5. Batteries and an electronic control system

I reduced the project to just five little systems. If attacked one at a time, the project didn't seem too terribly difficult. I decided to start with the generator. My online research showed that a lot of people were building their own generators. That seemed a bit too complicated, at least for a first effort. Others were using surplus permanent magnet DC motors as generators in their projects. This looked like a simpler way to go. So I began looking into what motors were best for the job.

A lot of people seemed to like to use old computer tape drive motors (surplus relics from the days when computers had big reel to reel tape drives). The best apparently are a couple of models of motor made by Ametek. The best motor made by Ametek is a 99 volt DC motor that works great as a generator. Unfortunately, they are almost impossible to locate these days. There are a lot of other Ametek motors around though. A couple of their other models make decent generators and can still be found on places like Ebay. This web site talks about the virtues and vices of various Ametek motors when used as generators. http://www.tlgwindpower.com/ametek.htm

I managed to score one of the good 30 volt Ametek motors off of Ebay for only $26. They don't go that cheap these days. People are catching on to the fact that they make great wind generators. Other brands will work, so don't fret about the price Ameteks are going for. Shop wisely. Anyway, The motor I got was in good shape and worked great. Even just giving the shaft a quick turn with my fingers would light a 12 volt bulb quite brightly. I gave it a real test by chucking it up in my drill press and connecting it to a dummy load. It works great as a generator, putting out easily a couple hundred Watts with this setup. I knew then that if I could make a decent set of blades to drive it, it would produce plenty of power.

There is more information on how to choose a motor for use as a generator on my web site at http://www.mdpub.com/Wind_Turbine/

Step 2Making the blades

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Blades and a hub to connect them to were the next order of business. More online research ensued. A lot of people made their own blades by carving them out of wood. That looked like an outrageous amount of work to me. I found that other people were making blades by cutting sections out of PVC pipe and shaping them into airfoils. That looked a lot more promising to me. This web site tells you how to make a set of blades for a small wind turbine using PVC pipe.

http://www.yourgreendream.com/diy_pvc_blades.php

I followed their general recipe. I did things a little differently though. I used black ABS pipe since my local homecenter store just happened to have pre-cut lengths of it. I used 6 inch pipe instead of 4 inch and 24 inches long instead of 19 5/8. I started by quartering a 24 inch long piece of pipe around its circumference and cutting it lengthwise into four pieces. Then I cut out one blade, and used it as a template for cutting out the others. That left me with 4 blades (3 plus one spare).

I then did a little extra smoothing and shaping using my belt sander and palm sander on the cut edges to try to make them into better airfoils. I don't know if it's really much of an improvement, but it didn't seem to hurt, and the blades look really good (if I do say so myself).

Step 3Building the hub

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Next I needed a hub to bolt the blades to and attach to the motor. Rummaging around in my workshop, I found a toothed pulley that fit on the motor shaft, but was a little too small in diameter to bolt the blades onto. I also found a scrap disk of Aluminum 5 inches in diameter and 1/4 inch thick that I could bolt the blades onto, but wouldn't attach to the motor shaft. The simple solution of course was to bolt these two pieces together to make the hub. Much drilling, tapping and bolting later, I had a hub.

Step 4Building the turbine mounting

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Next I needed a mounting for the turbine. Keeping it simple, I opted to just strap the motor to a piece of 2 X 4 wood. The correct length of the wood was computed by the highly scientific method of picking the best looking piece of scrap 2 X 4 off my scrap wood pile and going with however long it was. I also cut a piece of 4 inch diameter PVC pipe to make a shield to go over the motor and protect it from the weather. For a tail to keep it turned into the wind, I again just used a piece of heavy sheet Aluminum I happened to have laying around. I was worried that it wouldn't be a big enough tail, but it seems to work just fine. The turbine snaps right around into the wind every time it changes direction. I have added a few dimensions to the picture. I doubt any of these measurements is critical though.

Next I had to begin thinking about some sort of tower and some sort of bearing that would allow the head to freely turn into the wind. I spent a lot of time in my local homecenter stores (Lowes and Home Depot) brainstorming. Finally, I came up with a solution that seems to work well. While brainstorming, I noticed that 1 inch diameter iron pipe is a good slip-fit inside 1 1/4 inch diameter steel EMT electrical conduit. I could use a long piece of 1 1/4 inch conduit as my tower and 1 inch pipe fittings at either end. For the head unit I attached a 1 inch iron floor flange centered 7 1/2 inches back from the generator end of the 2X4, and screwed a 10 inch long iron pipe nipple into it. The nipple would slip into the top of the piece of conduit I'd use as a tower and form a nice bearing. Wires from the generator would pass through a hole drilled in the 2X4 down the center of the pipe/conduit unit and exit at the base of the tower. Brilliant! (if I do say so myself)

 

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Small Wind Powered Generator

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As far back as I can remember, I've all ways wanted to make a wind generators.
My 1st and only attempt was back in high school, when I had built one using wooden blades and turning a bicycle generator.

So after getting hooked on Instructables .com and viewing other members wind mill projects, I've been on the lookout for DC motors and thinking of some ideas.

Then one night it hit me.... I had an old cordless drill that I was no longer using.
So after finding and disassembling the drill, is when the brainstorming began :)

The chuck tightens down perfectly on the gear that is attached to the motor, which this in turn provides a "hub" for a larger disk for the blades to be attached too . The
blades will have to spin in a clockwise direction to keep the chuck tight.
I cut in half a section of pipe that is slightly larger than the outside diameter of the friction bearings that are between the hub and the chuck. I then used an water hose
repair connector to hold the cut pipe halves around the friction bearings which also will provide support.
I attached the assembly to a plastic peg board.
After attaching the blades and hooking up a voltage meter, I took it outside in a very light wind.

The completed unit spins freely and the small DC motor does create a small amount of DC current.
I can/could install a bigger motor using the "chuck".

The day I mounted it atop a pole, a thunderstorm came up with high winds and the wind turbine handle it just fine.

After this "intro", I'll show my progress in "steps".

Step 1Step(s) after intro.....

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After getting the unit assemble/attached to the peg board, it fit perfectly inside an 10 oz coffee can

Step 2Mounting the unit

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I found an adjustable closet rod that I'll mount the assembled unit on to.

Step 3Up and going

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The wire is fed down through the rod and tubing and comes out near the base of the tubing.
With the turbine being painted in a camo scene, it almost isn't noticeable against the tree line.
I live in a low wind area, but it does spin in very light breezes.

Step 4Prep work for the larger motor

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The larger motor fits perfectly into the 10.5 oz coffee can. I cut the bottom off of the can and shoved thick packing foam between the motor and can, then put the plastic top on the bottom of the can
I put silicone around the top of the can and the front plate of the motor.
This motor being an high RPM motor, I'm afraid that it won't produce much more power.
But for $18 and $7 shipping, it's worth a try.

September 2011....
This motor was a flop!
It worked great as for fitting in the can, mounting to the mill and the chuck / blade assembly. But I was lucky to get .5 volts in a steady wind.

Step 5Larger motor up and spinning

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My son and I got the larger motor up and spinning sooner than I had planned.
Like I had mentioned in the previous step, this motor put out very little voltage.

Step 6On the farm

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After 6 weeks of watching it spin and weather through high winds from thunderstorms, I figured it was time to put the generator to use.
I have a solar LED lighting system at my parents farm house.
So I drove a metal fence post into the ground and then attached the windmill mast to the post.
Ran a old phone cord about 8' high from the mast to their front porch.
I soldered a blocking diode to a lead and then hooked the leads straight to one of the 12 volt dry cell batteries.
With the small amount of power that the motor/generator puts out, I figured it was OK to bypass the charge controller.
I shoved lots of extra wire back into the mast, in hopes that it would take a long time before the wire would get too twisted from turning into the wind(s).

Step 7Test model # 2

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Here are images to some ideas that I'm working on for my 2nd test model.
The chuck is from an old Dewalt (R) cordless drill.
I used 2 blocks of wood to secure the motor/generator inside the "U"  bolt.
The bearing is resting on a block of wood with a "key hole" drilled through, then the assembled unit is mounted to the board using the "U" bolt that is holding the motor. (lost the image)

The 6 blades are made from 3" PVC pipe, 18" long, mounted on a small metal disk.
They spin fast!

Covered the assembly with 3" PVC pipe and end caps.

Bolted a floor flange to the bottom of the board with an 1/2" X 10" pipe screwed into the flange.
Then the 1/2" pipe was slide into a 1" X 10' conduit.

The fin is made from a piece of scrap metal.

8/28/11
It almost hit 6 volts during a gust on a fairly breezy day

9/11/2011
I took this unit and hooked it up to the charge controller on the solar set up at my mom and dad house.

Step 8Geared

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This unit is using the chuck and geared hub from #1, just reversed.
The gear on the motor matched the gearing from the chuck/hub.
I mounted the motor and chuck/hub to a thin metal plate, then bolted the plate to the windmill.
I used 4" PVC pipe and caps to enclose the motor and chuck/hub.
I'll experiment with blade designs for both speed and torque.

10/03/2011
I installed 4 larger blades made from 4" x 2' PVC pipe.

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