Abstract: A feedback control system for a pulsed direct current (DC) arc welding system is disclosed wherein the duty cycle of current pulses supplied by a power supply is controlled in response to resistance sensed at the arc gap of the system. The circuit comprises a voltage sensor, a high-low regulator, and a pulse width signal generator. The voltage sensor senses the voltage drop across the arc gap. This voltage is directly proportional to the resistance at the arc gap. The high-low regulator responds to the sensed voltage to generate an output signal when the voltage drop across the arc gap exceeds a high limit or is below a low limit. This output signal alters the control signal from the pulse width signal generator which controls the arc welding system power supply.

Abstract: A control system for a pulsed DC arc welding system power supply is disclosed. The control system operates to automatically adjust the pulse width of the current pulses supplied at the arc gap by the power supply to control the power flow to the work pieces at the arc gap. An example of such a control system for a conventional pulsed DC arc welding system power supply comprises a variable resistance device connected in parallel with a normally closed time delay switch. This system is electrically connected in an impulsar control circuit of the power supply. The control system automatically changes the resistance within the conventional impulsar control circuit to provide an adjustment within the control circuit to alter the impulsar output signal which controls the pulse width of the current pulses supplied by the power supply.