Homebrewing a Real Wind Generator...

This semester, in addition to learning tower-climb competence and tower rescue techniques, my small-wind power students are building a "homebrew" wind generator, from scratch. I got to be involved in a project like this back in June, and now I'm sharing the experience with my Community College students.

We started with blade carving. These laminated, cedar blades are designed with a 5:1 tip-speed ratio, and an angle of attack to the apparent-wind of 4 degrees. By design, the blades taper to the tip and have a slight twist from the root to the tip.

https://farm8.staticflickr.com/7474/...204f8f0fa5.jpgBlade Carving 03 by tjwilhelm148149, on Flickr
https://farm8.staticflickr.com/7520/...28e03cca6f.jpgBlade Carving 02 by tjwilhelm148149, on Flickr
https://farm8.staticflickr.com/7544/...7683ae6b12.jpgBlade Carving 05 by tjwilhelm148149, on Flickr
https://farm8.staticflickr.com/7561/...b4238bde5f.jpgBlade Carving 01 by tjwilhelm148149, on Flickr
https://farm9.staticflickr.com/8615/...928f103dee.jpgBlade Carving 07 by tjwilhelm148149, on Flickr
https://farm9.staticflickr.com/8635/...f4b2f3947d.jpgturbine 01 by tjwilhelm148149, on Flickr

Next, the students built a simple, coil-winding jig and wound nine armature coils. Then they assembled the coils for the 3-phase, wye-wound stator. The stator is ready for soldering and then will be cast in resin as a large, "pancake" ring. This is a flat, axial-flux alternator.

https://farm9.staticflickr.com/8632/...aa6bc5671a.jpgcoil jig 01 by tjwilhelm148149, on Flickr
https://farm8.staticflickr.com/7516/...1dd9425e77.jpgcoil jig 02 by tjwilhelm148149, on Flickr
https://farm8.staticflickr.com/7566/...9aa6a99e24.jpgcoils 01 by tjwilhelm148149, on Flickr
https://farm8.staticflickr.com/7576/...900f15a516.jpgcoils 02 by tjwilhelm148149, on Flickr
https://farm9.staticflickr.com/8655/...910f730394.jpgAlternator 02 by tjwilhelm148149, on Flickr

The other half of the alternator is two, revolving-field, permanent-magnet rotors. One rotor is on each side of the stationary armature (stator), like bread hugging salami in a sandwich. These rotor plates are steel, with properly spaced, and VERY high-strength neodymium magnets.

https://farm8.staticflickr.com/7566/...cced59d473.jpgAlternator 01 by tjwilhelm148149, on Flickr
https://farm8.staticflickr.com/7497/...0d05d8c208.jpgAlternator 03 by tjwilhelm148149, on Flickr

Here's a short video I made showing how I tested and confirmed the students' work...

https://www.youtube.com/watch?v=4VntMpBWdNg

Very cool project.....what is the target out-put?

It's hard to say, hunter63. This is because the power output of wind machines is so dependent on wind speed. It has a 10' diameter turbine, so we can ballpark the output like this -- if the average windspeed is 12mph, it should produce about 2,500 kWhrs/year.

Christmas break is upon us, so our project is going on hold until next semester. I'll update in January.

That's a pretty cool project. I look forward to the rest of the pics. Thanks for posting!!

Awesome project TJ.

Looks like a fixed hub....so.... for high wind speeds, the blades get tilted out of the way?.......I sure there is a name for that but can't remember what it is.

Fancy. The name is fancy.

Or dandy. That could be considered a real dandy.

hunter63 -- the word you're looking for is furling. Yes, this will be a side-furling machine. That means, in VERY high winds, the tail will stay aligned with the wind, but the turbine/blades will be turned 90 degree away from the wind. If the wind gets too high, the generator can put out so much current the machine could burn up its own windings. Furling prevents that damage from occurring.

Quote:

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Originally Posted by tjwilhelm

hunter63 -- the word you're looking for is furling. Yes, this will be a side-furling machine. That means, in VERY high winds, the tail will stay aligned with the wind, but the turbine/blades will be turned 90 degree away from the wind. If the wind gets too high, the generator can put out so much current the machine could burn up its own windings. Furling prevents that damage from occurring.

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I can recall that there was a word...Rick and Crash...see I wasn't just having a senior moment.....Naw naw naw...boo boo

Thanks TJ good stuff......
Says I gotta spread rep.....

Took care of it H.

We did this in my high school engineering class except we made the blades out of ripped down pieces of pvc pipe and used a modified car alternator for the generator, ill try and find pics. Cool project!

Couldn't find the pictures of the ones we made but here is a pic from the interwebs like the ones we made.

http://www.rlocman.ru/i/Image/2009/11/03/12.jpg

Our testing found that our turbine was most efficient with two blades instead of 3, we think the 3rd blade was just adding drag. We messed around with making a one bladed turbine but it didn't pan out.

Innovative!

FYI

Mother Earth News had a couple or projects back in the 1980's.....
Red Baron
http://www.motherearthnews.com/renew...#axzz3MB7pDRgo

Blue Max

http://www.motherearthnews.com/renew...#axzz3MB89gwGt

I cheated.....after years of screwing around with cobbled up half factory half home made wind generators I bought a 5 blade from Missouri Wind and Solar......the blades are carbon graphite and are well balanced.....been up about two months........works well. Starts doing its thing at about 6mph.......I have an anemometer on a pole same height as generator.........just 2 months into it so time will tell about its durability

Very nice, Im impressed!

1) I work in the power transformer industry (power distribution, sub station) so I am familiar with the Wye winding, AC and sine wave, etc.. Anywho, I am hoping the plate the magnets are attached to are either aluminum or stainless thus being non-magnetic.

2) Just curious, why chose this design over a VAWT?

3) Dont forget the 3 phase rectifier to DC (I am assuming your goal is DC output?) Its a little different than a standard setup, but the schematics make it easy to follow..
http://hackedgadgets.com/wp-content/...-rectifier.png
As shown with a Wye setup.

From what I am seeing, you have four Wye coils so your output should be pretty steady and respectful! Even two Wye coils are good, 3 better, but 4 is ideal. If you look at the waveform of four 3 phase windings, the AC peaks should convert over to a strong and steady DC power output!!! Well done!


What are your plans for voltage regulation and battery charging???

I encourage you to look at PIC microcontrollers to do monitoring and charging controlling.

Keep up updated!!

EB

For that matter, on the stupid simple and dirt cheap, the PICAxe microcontrollers are easy to get started with and WORK!!! Its what I worked with until I graduated to PIC and Proton BASIC.

https://www.sparkfun.com/categories/125

https://www.sparkfun.com/categories/124

I bought all my PICAxe stuff from SparkFun... I *hate* SparkFun, they have taken a LOT of my money! HA HA!
(On a serious side, SparkFun is the best electronics hobbiest component provider I have *EVER* dealt with!!)

EB