First prototype VAWT...

[davefdci]

First prototype running unloaded.

http://www.youtube.com/watch?v=kSoYDLBcgbQ

First protoype:  running a Bicylce hub motor.  Approximately 8 volts in 15mph with a 10 ohm power resistor.  Too low!

http://www.alibaba.com/product-gs/205441323/hub_wheel_motor.html

[vawtman]

Cool vawt Dave,

 Do you have a still pic of the blade design?Also just before the video shut down you were talking about nickel metal and?

 Thanks for showing and sharing.

 Mark

[davefdci]

Here is another shot of it running with the bike hub motor.  There is a slow motion section on the video..

http://www.youtube.com/watch?v=Ed3nPQMS6YM

I will try to learn how to post still pictures of the design.  It is a symetrical NACCA 63 foil profile that I wrote a short program to "wrap" the foil around the center pivot.

It seems to work well but I've made a strategic mistake in designing it to turn too slow.  I think I need to find a way to build another one much faster.  

[vawtman]

The load may be too fast for the turbine.I'm sure that little hub motor has little or no effect on it.Am i right?

 Gearing is a killer and low solidity can be scarry and stall easily.Also hard starting.

 I think your good and just need to match the load.Not easy

[davefdci]

Yea... I do feel like I'm kind of poking around in the dark.  Like everyone I'm trying to work with what i have on hand which can be really limiting.  The initial gear drive actually worked pretty well although I only got 2VDC out of the motor I was using.  This was a 10:1 gear ratio on a small motor designed to run at 12VCD at 3100 rpm.  I was probably running 1200 rpm into the motor so it's no wonder.  

I continue to be very confused about how to size an alternator to match my desires.  I've found equations that will predict the power output of the blades but how does one go ahead and match that to a power source?

My objectives are modest - 25-40 watts charging a 12VDC battery.  

Any suggestions?

FYI, I'm thinking of abandoning this appraoch (combination lift-drag) and going instead to the Sandia savonious design I've read about on here.  Any epxereince with that?

Thanks for the sympathetic ear.

Cheers.

[CmeBREW]

Thats a nice Darrieus Vawt there! Good work Dave.  Thanks for the video and the slow-motion. Great shot of the blades and angles.

Those look really neat.  If you can make a good matched alternator to it, I am certain you will easily get your 25-40 watts and more, IF you can make the alternator Efficient enough.

I'm glad your expectations are reasonable.

You will want to keep that nice Darrieus rotor and keep trying to match a proper alternator to it. It is not easy but that is the fun quest.

It is faster rpm than my small Lenz2 version Vawt.(and mine is only 26" diameter at this time)

That faster rpm is nice.  I think I would like to make one of those also in the future on my roof. They look like a radar or something.

Can't wait to see your Savonius too.  They are slower rpm, so match an alternator is even more difficult I think.

I was about to give up on my countless Vawt experimentations lately and take an Axe to mine, when finally, after shrinking the diameter down 5 different times over many days, the thing finally started making some little consistent power for the first time. (not just a big wind gust like the past)

Heres a picture of it today:

 

I have been working on it and many other numerous Vawts for over a year now.  But only now am I starting to get something real into the 12v battery.

All day today it did 2-4 watts in low wind, and then when a thuderstorm was approaching, it did a lot of 20 watts+ , and a few times in a big wind gust it did 40 watts!  

And I know I can make it better and better.

So keep up the good work.  For those who can't put up a Hawt these really look neat and you could put up many I think since they look like art.

I will be writing a posting in my Diary about this with pictures very soon.

Feel free to email me on the specifics of my alternator.

I have learned a few things to make it much better. (bigger neo-magnets and thus less resistance, and therefore more power made in any given wind)

-Keep up the good work.

[wooferhound]

You need to design an alternator that will work in the RPM range that your VAWT spins at. Most VAWTs start working good at around 60 RPM, yours looks faster in the video. If you are using a system voltage of 12 volts then you want your alternator to start making 12 volts (Cut-In) in the Low RPM range where your VAWT starts spinning good.

You would build a larger diameter alternator because you will have bigger coils. Make your magnet rotors and assemble the machine without the stator. Then start winding Test Coils. Spin up your magnets to your Cut-In speed and put coils in between the magnets while making electrical measurements of their capabilities. Once you get a coil that performs to your design voltage, just duplicate that coil and build your stator and complete the machine, knowing already the speed that it will start charging the battery at.

[commanda]

My first reaction looking at your video;  You need less diameter and more height.

Amanda

[electrondady1]

nice work.

may i suggest a less vulnerable support mechanism!!

or give them a helmet at least!

or you may run short of assistants soon.lol

can you adjust the angle of incidence?

if so , check out how that will effect start up and lift.

at what rpm does that  alternator(bike motor)  produce 14 volts?

matching the alt to a vertical seems to be the biggest stumbling block to be overcome

notice the placement of the alternator on cmebrew's set up

.

with the alternator /support in the middle the wind will load the vanes evenly .

(cmebrew, your mill is looking slick ! why not post the details of the changes you have made)

[vawtman]

I'm working on an alternator design that could use a pulley for the rotor(radial).My pulley is an old baler wheel but the turbine is an 8ftX8ft Darrius.

 Depending on the no. of poles you could charge a battery with one coil.The airgap will be adjustable to match the turbine.Mags would only be on the main rotor.I named it Vawternator :V)

 Ive spent alot of time on it lately.

 Darn camera does'nt recognize the puter anymore.I'll figure it out.

 Stick with it.I know it runs silent.

[Stonebrain]

Hi davefdci,

Looked at the pdf file.

It looks great,although I don't like mounting a high rotor with only a bearing at the base.This will give very high bending force at the base and materials must be very strong for not getting fatigued under load for long periods.

For testing such a design is very good but for real energy production I'm more to a H-design.

Amanda's suggestion is good for getting higher rpm's,but is much more demanding on mechanical strength and balancing.

If you want to have some information about the relationships between rpm,windspeed and torque,you need to build a 'prony break'.Unless you're very good at guessing about the alternator you have to build,you CANNOT get around this.

This point have been mentioned numerous times in relation to vawts,but still nobody has presented a working proposition for such a device.I myself have done some efforts but  not very succesffull untill now.

Since all the vawt designs are experimental,wich means that nothing is known about the performances of those rotors,mearurements with a prony brake are necessary if you have no idea about the alternator to build,for not continuing talking in the air.

I have build a very simple device now,maybe I will present it in a separate posting but I will only test it when I finished building my new rotor.

cheers,

Jaap

 

[Stonebrain]

"If you want to have some information about the relationships between rpm,windspeed and torque"

have to add "under different loads"

[CmeBREW]

It seems to me that it doesn't really matter that much where you put the generator, rather it is on the top the middle or the bottom like the Lenz2.  Its really just a matter of making it stable and strong enough to hold together and stay straight when the big wind gusts come around. These can really spin fast in a storm!

I put mine in the middle mainly because of looks, cheaper, easier, and just plain good ol' fashion laziness.  I may change it later, but for now it passed some big wind gust tests with flying colors, and I only had half the mounting bolts in each blade due to testing.

One good thing though is that with the genny in the middle you don't have to have the added friction from the extra strong bearing at the top or bottom.  I could also fasten the top and bottom of the blades together with flat steel pieces if I wish.  I will post about it real soon (few days)-- there is a lot to say and I want to make it interesting so we can all hopefully get some ideas and maybe ED will say some things too.

Concerning Dave's nice Darrieus Vawt I just wanted to say that from everything I have read and videos I have seen on those, it seems they have a difficult time starting up, especially in low wind.  I wonder if Dave had this problem also.  I know I did.  On youtube you see many times what they do is put a Savonious vawt in the middle of a Darrieus Vawt to help it get started.

I don't like the Savonious Vawt that much myself. The drag is a nightmare on the opposing/returning side.  I think the Lenz2 is MUCH better. Just an idea-- you might think of putting a smaller diameter Lenz2 in the middle of that Darrieus to help it start. Similar to the one I just showed.  

I am a big fan of the Lenz2 now that I have done hundreds of experiments and actually made many different vawt prototype attemps which failed for the most part.  

You might consider making a Lenz instead of a Savonious. I got mine at a different angle though. (10 degrees outward instead of inward like ED's)

-Just a thought.

-Please be careful with testing these Vawts or Hawts near the ground. They can be VERY dangerous from the inertia.  

Looking forward to your progression-- you're work looks impressive.