Hello to everybody,
I´ve been on a stone quarry where there is a big machine to make sandbags and other things. On the electrical box there are two frequency variators of this Lenze EVS9322EP.
First time people from the stone quarry contacted me to repair one of the modules. I saw at different components damaged at power board and the main IGBT module (BSM10GD120DN). As there wasn´t so much different in price between IGBT + components + time and the complete power board I decided to replace the board.
People from the stone quarry told me they had repaired the motor which was burnt.
When we installed the repaired frequency variator again it was damaged, exactly same problem at IGBT and I saw same phototransistor to IGBT signal damaged. We saw the other one for controlling another different motor also was damaged at IGBT board.
Now I have 2 of them damaged, I have to go and check the electrical installation, motors and so on.
I would like to know if you have tricks to verify and discard any problem on the control board because I want to be sure that when I replace again the power board on the frequency variator there isn´t any failure inside. I would say problems are external to the units. As I have to take spare board from China I would like to check as deep as possible the function of the modules without installing them. Sure, I know it´s difficult, they are 400V three phase input and also three phase output, connected to a main unit for command the modules...
As always, I don´t have any schematic but I think usually power board is isolated from control board so when it´s damaged is not damaging driver board.
I´ll pass you some pictures when I have more time. Sorry for the long history but they need to use the big machine and they contacted me to troubleshooting and repair all.