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yahoo2
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Posted: 20 May 2018 at 7:10pm | IP Logged Quote yahoo2

Achilles wrote:

Also, the dump is only utilized if the grid fails, is that correct?


I dont know, what happens when your controller reaches its limit? my opinion is it will fry the MOSFET's, I dont think a 2kw inverter is big enough to handle that turbine.

I would have thought that the inverter needs to cater for the max power (3.2kw) of the turbine at 20+ m/s not the rated power (2kw) of the turbine at 9 m/s.

I would think that any time there is a fault of any kind, either in the grid or in the inverter it will switch on the dump load not just during storms.

This turbine is rated 2100watts at 9 m/s, that is only 32 km/h, where I live that can happen any day of the week.

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Thai
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Posted: 27 May 2018 at 11:02am | IP Logged Quote Thai

So did you figure what's wrong? I'm having the same problem with fp to 22v inverter gti. Please let me know how u fix
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Thai
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Posted: 01 June 2018 at 1:21pm | IP Logged Quote Thai

Check your resistors. If you replaced them or damaged them, they can slow down your turbine. I had to try everything in the book to figure it out. Last thing I thought would be the cause is the dump load. Of course when all the windy days are gone I figured it out. Had 20mph winds and I missed it
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Achilles
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Posted: 02 June 2018 at 10:19pm | IP Logged Quote Achilles

Hi everyone,

sorry for the delay.

I was able to test a 45-90V inverter and it works much better.
The turbine spins up to much more rpm than with the 22-60v inverters and even in slow wind conditions (like 3m/s).
It then reaches 40-45 volts at which point the inverter kicks in.

Apperently the 22-60V inverter put too much load on the generator too early.

Since a single 2000W inverter cannot handly this turbine, I'm getting 2 of those and run them in parallel. I will adjust the current curve so that each inverter draws only half the current.
I tested this config with my 22-60V inverters and it does work properly.

So with this setup I will not run each of the inverters at more than 80% load, even during storms.

As a dump load I plan to use 2mm fence tensioning wire which I will wind around bricks. I have hundreds of meters of that stuff lying around.

Quote:
This turbine is rated 2100watts at 9 m/s, that is only 32 km/h, where I live that can happen any day of the week.

Yep, I know. We had a few thunderstorms last week.
My weather station recorded wind of 50 km/h (31mp/h) and gusts of up to 66 km/h (41 mp/h) and the weather station is about 2 meters (6 feet) further down.
I'm glad I shorted the generator before the storm.

Edited by Achilles on 02 June 2018 at 10:24pm
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Posted: 02 June 2018 at 11:06pm | IP Logged Quote yahoo2

Good work!, sounds like you are getting your head around it.

if your wire is soft enough you can measure the resistance of a length of wire, fold in half stick the two cut ends in a vice and twist the folded end to halve the resistance if it needs to be bigger.

when I used to put up turbines it would either be dead calm for days or blowin its arse off. I'm sure i was jinxed.

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Posted: 03 June 2018 at 11:03am | IP Logged Quote DaveP68

Hi Florian

Good to hear the 45-90 V GTI worked as I suspected it would.

Achilles wrote:
Since a single 2000W inverter cannot handly this turbine, I'm getting 2 of those and run them in parallel. I will adjust the current curve so that each inverter draws only half the current.
I tested this config with my 22-60V inverters and it does work properly.

So with this setup I will not run each of the inverters at more than 80% load, even during storms.


Sounds like you have this under control. Also handy feature being able to control the start current too. This will be important when stacking them.

So they can now be programmed?

On an earlier generation of this type of inverter I did a hardware modification so only one inverter started at cut in around 44 V pulling about 0.44 Amps. The other inverter started up at 48.5 V far enough apart in voltage that the blades had built up enough energy to run the dual inverters. Used a zener diode in series with volt drop resistor on voltage sensing A/D input. Worked great.
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Achilles
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Posted: 04 June 2018 at 6:43pm | IP Logged Quote Achilles

Quote:
So they can now be programmed?


They can, check the picture.



But not the start current which was the issue with the low voltage version of this inverter.
Once the 45-90V model starts up it actually works all the way down to 40V which is very nice in low wind speeds.

I'm curious about how well the dump is going to work.
I will post some pictures once I have built the resistors.

I will also let you know how well 2 of those work in a stacked setup.
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Posted: 13 June 2018 at 2:04am | IP Logged Quote Achilles

Quote:
On an earlier generation of this type of inverter I did a hardware modification so only one inverter started at cut in around 44 V pulling about 0.44 Amps. The other inverter started up at 48.5 V far enough apart in voltage that the blades had built up enough energy to run the dual inverters. Used a zener diode in series with volt drop resistor on voltage sensing A/D input. Worked great.


I may have to do that as well.
The 2nd inverter arrived today and after installing it I observed that the blades did not speed up as much as it was the case with a single inverter. (I modified the voltage points to split the current evenly between the 2, modification is only possible from 48V upwards though.)

I will wait and observe before I modify the hardware though.
Today wasn't particulary windy.




Can you tell me what kind of zener diodes you used, or just send me a link to the forum thread, if there is one?

Edited by Achilles on 13 June 2018 at 2:05am
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DaveP68
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Posted: 13 June 2018 at 6:14pm | IP Logged Quote DaveP68

I can't remember the exact value wasn't my inverter. The zener could have been 5.6 Volts 200 mW surface mount. Would need to know the resistor divider ratio on the A to D input which I didn't record to confirm.

Without a circuit diagram I just traced the parts to work out how to do it on the day.
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