Thyristors back to back are usually fired with pulse transformers across C and G, not opto couplers
I did not understand.If switching the same phase, which you appear to be, then why not a Full wave bridge? Two rectifiers, two SCR's
the power section of my attached image is a spot welder exist, but its control/firing circuit has been defected, so I ask if that control circuit will work if implementedIt can be done with a full wave bridge with either SCR's in the bridge or a bridge followed by a Triac.[/ATTACH]