Good grief... the whole lot's is shot I'm afraid.
I suspect your smaller control card was intermittent, and that probably led to some fet problem in the fet baord... putting the 15kw controller may have pushed your probably by then fet board too far.... and then took out it's drivers.... I suspect the whole lot is toast now.
The control cards may be fixable if the damage did not go past the opto and totem pole driver transistors... in which case fixable if you able to do that sort of work.
The better news is the fet cards are easy to fix... simply replace all the fets or at least all the fets that are short... and they are usually only 70c/piece.
This is why I developed the last board.... in this case I replace three plug in chips, and the fets and we are fully renewed.... chips about $5 all up.... fets $24.00 for the set max..
If you try to fix the controller, then use 1 fet in each leg only, until you get it working properly, you don't want to kill 24 each time you mess up, and it is hard to test the control card out of the system
Normally you could drive those loads easily with the 15kw board and controller.... how small is your smaller unit?.. usually 5kw units will start anything anyway, and they are self protecting if the board is fully functional... your had a fault... you may get a new board/s for free if it is recently purchased.
I would urge you to try to build my little board, It seems to work fine, and you can tune your voltage and current points as you want..... I have not been able to kill a 8kw fet board with the new controller, no matter how hard I try to push it.
Remember, if you use the 002 design to remove the 393 and do the pin bypass on it, and change the resistors on the gates on the fet board to 5r6 and put diodes across them... read that whole thread a few times until you get the feel of what I did, what worked, and what did not.
Hopefully PJ will replace the boards free.
..............oztules
