3 single phase VAWT waiting for wind

[(unknown)]

I completed the installion of 3 single phase vertical axis wind turbines.

I purchase a small CNC router to aid in the fabrication of the blade supports and rotors. It is a Zenbot, great bang for the bucks. The only downside is the Mach3 software, it has a problem, there is a accumulative offset of 0.0009 of a inch after each axis moves that does not show up on the digital read outs. I am now using Kcam software and it works great. I can draw a part using TurboCad to create a .dxf file. Open the .dxf with lazy cam Pro to create the G-code and use the G-code file with Kcam to cut the parts.

I tested the alternators with a variable speed lathe and a auto head light for a test load and they max out at 5 amps @ 16.3 volts @ about 700 RPMs.

I am looking for a circuit that will allow me tie the 3 turbine together for a higher voltage at lower wind speeds. If anyone has any ideas please let me know.

[electrondady1]

like i said congratulations .
try a google search for a step up transformer.
maybe you would need three?

[GeeMac]

I am not an expert, but it seems to me that if there is a bridge coming off each vawt then you can join the wires together after it passes through the bridge. But you said yours is single phase, so perhaps just a diode will do the job. (4 diodes can form a bridge - find out how to make one on this website.)

[electrondady1]

yea i've got two single phase  vawt mills up now and they are combined after the rectifyer in parralel  it increases the amps but i wasn't looking to increase the voltage .
if you  hook them up in series after the rectifyer i guess that would give an accumulative voltage.
 

[ruddycrazy]

G'day Kilroy,

             Is that a huge batch of PV panels right next to the vawts . If so I'd be making damn sure those vawts don't over speed in a storm and fly apart into those PV's.

Cheers Bryan

[KilroyOdin]

Hi, it just the greenhouse.

[TomW]

KilroyOdin;

What is the scale [size] of this unit?

Looks like fun stuff.

You can use 3 single phase transformers to make a 3 phase unit. Gets big and heavy fast tho as you go up in power handling.

Tom

[s4w2099]

Or just tie them together in parallel and use a boost converter. Simpler IMO.

[CmeBREW]

Nice looking Vawts KilroyOdin.  I like the look. Reminds me of a sortof 'Bamboo Temple' in the Amazon.

I like Geemac's idea (I'm no expert either) of the bridge rectifiers.  Maybe try making a simple circuit separated with a few typical spst switches, and use three additional bridge rectifiers hooked in SERIES for much higher voltage in low wind.  I'm not sure if it's possible to do it without the 3 spst 'cut-off switches' though.

On low wind days you turn the switches 'on' for low wind 'trickle charging', and on windy days turn them off for normal higher parallel current charging. (just an idea)

I do something similar with my little 3-phase axial Vawt.  'Windstuff ED' gave me a simple 'voltage doubler circuit' with using 3-phase by using two fairly large MF DC capacitors and ONE bridge rectifier.

But all I have is two AC running capacitors and so I used them, and they seem to work OK, but they seem to do some weird things I am still trying to understand. I suspect I am missing half a phase (or more)somewhere.  They also delay charging a few seconds. But I don't need to use cut-off switches though-- I just leave this circuit hooked up to the normal bridge rectifier circuit.

But with my small power Vawt(only 6 sq. feet swept area) , this additional little circuit only usually does 1-4 watts on and off, up and down, in lower winds.  It just trickle charges.

I hate to say it but, Even though it looks impressive turning 60-80rpm when all my Hawts are not even moving, it is really just an illusion, there really is little power (real extra torque)there, it is just mostly free-coasting with the slow wind breeze. (unless one had a much bigger Vawt that is)

But I can't really tell the size of those Vawts of yours??

Also, Might want to experiment with some dc capacitors in addition to the Transformers TomW mentioned??

Keep up the good work.

[RP]

The hookup you're looking for looks like this (from Wooferhound's files):

That circuit will add the voltage of three phases together on a single motor but it may behave strangely in your case since the current flowing through the system loads the individual alternators in an unstable way.  Basically the turbine with the weakest output (even just a little less) may slow dramatically or even nearly stop due to the "electrical back-pressure" from the other two.

In any case it'll be cheap to try.  You just need three bridge rectifiers and some wire to hook it up.

The capacitors will be some help and they need to have a voltage rating at least double whatever your system voltage is and the highest capacity (in microfarads) that you can afford.

[ghurd]

I think it will work.

The bridges will act as a by-pass diode if one is stopped, meaning no the "electrical back-pressure" to stop one.  One may stall.

The caps can be attached directly to the bridges.  Only need the one wire running between windmills.

G-

[KilroyOdin]

Thanks . All comments are greatly appreciated.

Best Regards

[CmeBREW]

There is another possiblity that I think would probably be better than trying to hook the three up together, since it (seems to me) it adds the three Vawts resistance together to some degree (?) which limits current more, and in a low to the ground turbulant location such as that, the 3 vawts may often have problems turning with the same torque at the same time, reducing the total power collection even further.

Just today I evidently doubled the consistency and Watthours of my small 6-7 Sq.ft. Vawt by accident.  It was unhooked and spinning quite fast, so I quickly hooked it up to only 2 (instead of 3) of the phases while watching the ammeter.  I noticed a big improvement immediately. This is similar to your single phase Vawts.

Recall, it is hooked up to two AC running capacitors (200vac/ 70mF each I believe) hooked it SERIES and one bridge rectifier-- and I said I was getting decent but weird results.  

Well, now it is doing a LOT better and doing at LEAST TWICE the consistent power (WH) especially in lower turbulant wind.

Evidently, the voltage was much TOO high with all three phases going thru the high voltage capacitors, that the vawt was in some STALL in very low winds and breezes without me knowing it.  I also hooked it up to a big DC motor to make sure the power was real and not a trick, and joyfully, it was real. (and tried numerous meters)

From the results I am now getting, I have changed my mind when I said above:

"I hate to say it but, Even though it looks impressive turning 60-80rpm when all my Hawts are not even moving, it is really just an illusion, there really is little power (real extra torque)there, it is just mostly free-coasting with the slow wind breeze."

I am having much better results now with the vawt even turning slowly.(even under 60rpm / It even trickle charges barely moving 10rpm)  I'm not sure I understand it.

You might want to get some capacitors and try increasing the voltage on each of your Vawts Separately with this type of circuit in addition to your normal higher current circuit(s). I am going to get more capacitors from the 'Surplus Center' and try to make it even better. DC capacitors might be even better--I have no idea.

But be very careful though, I heard capacitors can explode in certain situations.

I really do not know much about capacitors and the limit of current they can handle or how to calculate it.  I'm just experimenting myself.  

[CmeBREW]

I made a mistake.

It WAS a trick that fooled me because of SOO many wires. One of the phases was PARTIALLY shorting the ammeter because it was hooked up wrong.  Sorry about that.  I really thought it was hooked up right. It is tricky.

It did not double the output like I thought.  It is the same as it was. I am getting 1-12 watts thru the capacitors though, but it takes a good gust of wind to get 12 watts and the vawt is really turning fast to do it.  Somehow, the two capacitors in series do seem to increase the voltage way up past 45vdc, but it does not accept into the batts readily for some reason. There is a delay??

-Keep tryin.