Electric arc welding system

A power supply system comprising:

• a first controller for a first power supply to cause said first power supply to create an AC current by generating a switch signal with polarity reversing switching points in a general timed relationship with respect to a given system specific synchronizing signal to said first controller, said first controller operated at first parameters in response to first power supply specific parameter signals to said first controller;
• at least one slave controller for operating a slave power supply to create an AC current by reversing polarity of said AC current at switching points, said slave controller operated at second parameters in response to second power supply specific parameter signals to said slave controller;
• an information network connected to said first controller and said slave controller and containing digital first and second power supply specific parameter signals for said first controller and said slave controller and said given system specific synchronizing signal;
• and a digital interface connecting said first controller with said slave controller to control said switching points of said second power supply by said switch signal from said first controller.

A power supply system comprising at least a first power supply for delivering a first low frequency current;

• a second power supply for delivering a second low frequency current, each of said power supplies including a three phase voltage input operated at line frequency;
• a rectifier to convert said input voltage to a DC voltage link and a high frequency switching type inverter converting said DC voltage link to a high frequency AC current;
• an output rectifier circuit to provide a positive voltage terminal and a negative voltage terminal;
• and an output switching network operated at a given low frequency for directing a pulsating current at said given low frequency from said terminals;
• a master controller for creating a synchronizing signal alternating between a positive command and a negative command at a selected frequency, means for driving said first power supply by said synchronizing signal wherein said frequency of said first current is a function of said selected frequency;
• means for driving said second power supply by said synchronizing signal wherein said frequency of said second current is a function of said selected frequency;
• means for delaying said synchronizing signal to said second power supply to phase shift said second current from said first current;
• and means for operating one of said power supplies at a frequency different from said selected frequency upon response to one of said commands from said synchronizing signal.