Hello everyone. I have made a system like this:
I have used 7 Irfb7430 mosfets from AliExpress and a timer module. I have changed the relay on timer module with a PNP mosfet and got a minimum 5msec pulse time. Made the probes with 35mm welding cables.
In short, I have prepared the system perfect as possible as I can do. I have tested the system with an oscilloscope before the welding process. But during spot welding, all the mosfets blown up. I remade the mosfet thing with 8 pcs IRF1404 but again all mosfets blown up. I only made the protection with skotcky diodes. I couldn’t make the tvs protection because I couldn’t find it in our local markets.
Do anyone have an idea what I am doing wrong?