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need ideas/advice/references on vawt model

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vobla

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Hi all,

I'm planning to build a vertical axis wind turbine, but first I want to construct a small model to get used to the process and experience pros & cons myself instead of dry reading.

I'm looking for ideas, advice or references to a good sources on this topic.

I divided project into 3 main parts:

* Mechanics;

I beleive I can handle mechanics. I'm looking at similar design:

**broken link removed**

* Power Generation - Alternator;

I have a lot of questions on this part. Anyone knows a *GOOD* source on this topic that would not be project specific?

In general I'm looking information on how to:
* Choose magnets;
* Choose coil wire;
* Choose number of winds;
* Estimate power output;

* Power Storage & Consumption - Electronics & Programming;

I'm looking to build a circuit to display rpm, wind speed and power output. IMHO first two mesurements could be achieved by processing AC signal from alternator (?). Then it would convert to DC and feed the battery if needed.


Thanks a lot!


P.S. I plan to document the progress and produce document on how to build VAWT with everything I know and will learn to give something back to the community.
 
Hi Volba,
That pic of the vawt is a Lenz turbine designed by Ed Lenz over at windstuff.com. There was a competition on the fieldlines forum a few years ago where a member would give $100 for anyone that could build a sustained vawt capable of 100 watts. That prize was never claimed and the general consensus is Vawts are only good for yard art and as far as power production on any scale goes forget it. HAWTS or horizontal axis wind turbines offer the best bang for buck and they are easily made.

Cheers Bryan
 
That is very interesting. Looks like I have to make a turnback on a main project.
Anyway, I would want to build a small Lenz model to practice electricity generation and use it to gather some data as stated above.

Never the less, I'm still looking for a good material on alternators. ;)
 
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Ok. I'm finally starting to pin some points here..

If P = 1/2 * ρ * A * v^3
where P - power in watts; ρ - air density in kg/m^3; A - swept area; v - wind speed;

And P real = P - [from 40% to 65%];

How do I calculate magnet power I need, to harvest P real?..

Now magnet retailers specify dimensions, which are only good to determine the size of the alternator, pull power in kg and some of them do specify the grade. I guess grade comes into play..?

And for the second step, I choose wire gauge to be able to handle required voltage, but how about number of winds?

Also, I guess there is not much loss if I use rectangular magnets instead of wedge, but coils should be elipsoidal in the case, right?
 
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Hi Vobia

Verts are not the best choice for power generating. You would be very wise to visit and study the lenz turbine.

Go to windstuffnow. com and read in depth what Ed has built. The lenz seems to be the best of the verts, But they need to be "big" About 3 times more mass / bigger that a hawt to give the same output.

"Start with a small one to get the idea of what is involved in building one..."

Smaller dia will spin faster......... Larger dia will spin slower, And have more power.

I would susgest you build the vert first and test it out. Then match a generator to it.

S. Simon
 
Hi Vobla

In order to suggest a coil /mag combo, we need the size, RPM range, to get the amount of tourque. As i sugested "last post" dia. of the turbine will change the RPM range, and tourque output. Build a smaller one first. If you build a 3 ft / 1 meter to start with, That will give you some idea as to what you can expect.

If you make it well it then could be matched to a generator after testing of rpm and tourque. I expect it would give about 30 watts at 12 volts.

Some points to ponder:
verts have no furling protection.
a vert running with no load will be reducted to about 50 percent when loaded.
They need to up in the air the same as a hawt to work well.

S. Simon
 
There is a lot of information at TheBackShed.com - Homegrown Power

Go to the forums and have a read.

I agree with Bryan1 as we both have been around wind energy for some time and a vawt is expensive for the return it will give.

If you intend to spend money on magnets then you will want the best return in energy for the dollars spent.

My magnets costed $400.00 and for that outlay in dollars i want to produce as much power as i can.

The better the magnets the greater the return in power, if you intend to use some cheap crap magnet you will get a low power crap result in return.

Many of us have played with wind energy for a long time and it always amazes me how the new boys on the block think they can do what the rest of us in the know, point out will not work worth crap.
The funny thing is they always disappear and never post their results, which proves to me what we tried to tell them they found out the hard way, after much cost and poor results.

The advice is build it to a proven design and work forward from there as it is hard enough to extract energy form the wind without starting with a loosing design to begin with, as a vawt is.

The simple fact is if they worked well enough you would see commercial vawt mills and you dont only kinetic art.

Pete.
 
Hi vobla if you must go with vawt one cheap alternator is a f&p washing machine motor they can be rewired for almost any rpm and will give you any power a vawt will make
 
You can check this site for more information about the windmill building instructions. **broken link removed**
 
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