Welding transformer current control circuit.

Thread Starter


Joined Sep 8, 2008
I have an old single phase 230V welding transformer. it's output welding current is determined by choosing one of the four current ranges. it has taps - not the moving core type. I would like to convert it so that it will be a dc output welder and to add a control circuit that will be able to set the output current continuously by using a potentiometer from zero (or almost zero), to it's max capacity - 150A. from what I have seen, it's generally done by using a bridge of scr's. I've seen on Aliexpress that they are offered at a reasonable price. so, the main obstacle is the control circuit that will drive the gates of the scr's. looking forward for your advise and circuit.


Joined Sep 30, 2009
It's more than what you are thinking. For the price of one of the new inverter welders that are made to work that way It's not worth the time or effort if you need to weld.