classic not coming out of resting

[len]

Hi,
    At last Imanaged to find out why my turbine sometimes goes wild! What happens is that if the turbine has shut down because my dump load has come in, afterwards when the turbine starts again it sometimes failes to come out of rest, with the result that the input voltage goes sky high.
Fortunately I have managed to get to the turbine and stop it, but the volts went to 180 plus! Not good ( its a classic 150) any ideas, it does not happen all the time.
len

[Halfcrazy]

Len
Sometimes if the turbine is already wound up the Classic may not catch it fast enough before the voltage goes over the operational limit in your case 150vdc this is one of the big reasons a Clipper of some form will be needed on most turbines.

[Robin]

Len, what turbine do you have?
We are building the pre-production run of Clippers in a week or two.

[len]

Hi,
    No it seems to happen when the turbine has stopped, the classic goes to rest mode, but as the turbine speeds up it seems to stay in rest mode, so you dont even need much wind to go overvoltage.
My present dump load only works on battery voltage so with out the classic connected there is no load to slow the turbine. I am thinking of using the AUX 2 to activate the dump load, but it seems a bit complicated so i have not done that yet.
Len

[boB]

Hi,
    No it seems to happen when the turbine has stopped, the classic goes to rest mode, but as the turbine speeds up it seems to stay in rest mode, so you dont even need much wind to go overvoltage.\
Len

Hi Len...
I don't quite understand what you mean when this seems to happen when the turbine has stopped (or shut down ??)

Why did the turbine stop ?  Did it stop because you drew more current on the battery side from your diversion load ?
If so, was the charge controller in Absorb or Float when the diversion load came on ?

I ask this because if the charging stage was in one of the MPPT modes, (Bulk or Float MPPT), then it would have stayed in
that mode unless a big gust of wind came up and brought the battery voltage up above the Absorb or Float voltage maybe ?

Usually a wind turbine will take enough time coming up in voltage when even gusts come up to give the Classic plenty of time to turn
on (if it was off before).

   When this happens, was the Classic already on and running or was it Resting ??

What kind of turbine is it and how much wind are you getting ??

Also, what is your battery voltage and could the turbine and wind possibly be so much power that the Classic is going into over-current ??

This happens a lot which is why a Clipper is almost always needed except when the wind is keeping fairly calm.

Thanks,
boB

[len]

Hi,
    Ok, well when my  the batteries have reached 55volts, my dump load comes on, then if the batt volts still increase the windings are shorted out (via surge resistors) so the turbine stops. The batt voltage sensor then times out after 3 min or so, and the turbine restarts. When the turbine has stopped the classic goes into resting mode, so far so good all is fine. BUt.. sometimes (not always) as the turbine voltage increases it fails to come out of rest into Mppt mode, which of course sends the voltage too high, I was fortunate enough to stop the turbine before any damage occured, 50 yard olympic srpint to the controller! AS to absorb or float, yes that has occured too , but only if my Batt voltage sensor was set to high (that would allow it to go into adsorb mode and because of that there would not be enough load on the turbine, hence in high winds go over voltage)
    Its a 1 kw Turbine, chineese. High winds , 25 mph, not possible to go over current max of 30 amps
regards Len

[Grizzo]

Len, have you fixed your problem yet and how did you do it if you have?

[len]

Hi,
     Sorry for late reply, been doing other things. In answer to your question,  yes I have solved the problem but only by adding an over voltage sensor on the three phase AC turbine output. The difficult part of that is you have very little scope with the voltage sensor as I only use two of the turbine phases so if the turbine out put phase to phase is say 50 volts, by the time its gone through the rectifier as DC into the classic is already getting too close to the max allowed for the Classic 150, so the adjustment for the voltage sensor has to be just right, if anyone want the specs of how I made the circuit I can email it to them.
         Of course you should be able to use the AUX 2 to do the same thing, but I have not yet figured out that yet as the instructions on AUX 2 look a bit complex to me, I would like a chapter and verse on the Aux set up before I try it. Its just too easy to  break the classic  messing with the turbine in strong winds. I need to figure a way of providing the cassic with a controlled over voltage situation to set it up for sure.
Regards Len

[boB]

Len, we can help you set up the Aux 2 Clipper function.  It's not too bad really.

Why aren't you using a 3 phase bridge rectifier ?  Would you use all 3 phases if you had one ?

BYW, a clipper should work better on 3 phases rather than just 2 phases since it should help
slow down the turbine better.
I don't suppose that you notice any vibrations using just 2 phases rather than 3 do you ??

boB

[len]

Hi,
    Sorry  I have not explained enough, I only use two phases  for sensing the voltage on the AC side of the turbine, when the relay kicks in it shorts all three phases (all three phases go through three separate surge resistors so its nice and controlled stop) . There is also a time delay of up to three mins before the restart so it give the surge resistors time to cool down. Yes a clipper with PWM is ideal, we are all waiting for your unit and price!!
   Re Aux 2, yes if you could talk me through that I will dispense with my previous sensing system,as I said  my concern for that is how do I get an over voltage situation without waiting for the big winds, to test it? I assume I would have to provide an input to the classic of say 100 volt DC? and then set Aux 2 to operate?
Regards Len