A three stage power source for an electric arc welding process comprising an input stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal, a network of switches switched at a high frequency with a given duty cycle to convert the input into a first internal AC signal, an isolation transformer with a primary winding driven by the first internal high frequency AC signal and a secondary winding for creating a second internal high frequency AC signal and a rectifier to convert the second internal AC signal into a second DC output signal of the second stage, with a magnitude related to the duty cycle of the switches; and, a third stage to convert the second DC output signal to a welding output for welding wherein the input stage has a regulated DC to DC converter with a boost power switch having an active soft switching circuit.

Three stage power source for electric ARC welding

A power source for an electric arc welding process, wherein the power source comprises an input stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal and an output in the form of a second DC output signal electrically isolated from the first DC output signal and with a magnitude of a given ratio to the first DC output signal; and, a third stage to convert the second DC output signal to a welding output for the welding process.

Power source for electric arc welding

Power sources are disclosed for electric arc welding or cutting processes, in which an interleaved multiphase switching converter is provided with a plurality of converter power circuits to convert a DC signal to a regulated signal suitable for welding.

Chopper output stage for arc welder power source

A three stage power source for an electric arc welding process comprising an input. stage having an AC input and a first DC output signal; a second stage in the form of an unregulated DC to DC converter having an input connected to the first DC output signal, a network of switches switched at a high frequency with a given duty cycle to convert the input into a first internal AC signal, an isolation transformer with a primary winding driven by the first internal high frequency AC signal and a secondary winding for creating a second internal high frequency AC signal and a rectifier to convert the second internal AC signal into a second DC output signal of the second stage; with a magnitude related to the duty cycle of the switches and, a third stage to convert the second DC output signal to a welding output for welding wherein the input stage and the second stage are assembled into a first module and the third stage is assembled into a second module connectable to the first module.

Modular power source for electric arc welding and output chopper

A constant current arc welder of the type in which arc current is regulated by thyristor phase angle adjustment, includes voltage feedback voltage control and current feedback current control, with automatic transfer from the voltage control mode into the current control mode when current has been established in the arc. A time delay allows smooth transfer to the desired current operative level by limiting the current inrush under an initial current reference and with a chosen feedback control dynamic characteristic current boost is also automatically provided when the arc voltage falls below a predetermined level.

Constant current arc welder

A semiconductor electronic chopper precisely controls the current to a welding arc in response to arc length as represented by arc voltage. The actual arc current is compared with a reference current to generate a switching signal which adaptively controls electronic switches in order to meet arc requirements. For manual welding with covered electrodes (SMAW), frequently referred to as ''''stick welding,'''' a slope control potentiometer is used to vary the value of the reference current when the arc length (voltage) deviates from a preset normal operating length (voltage). This creates a family of volt-ampere characteristic curves all passing through the preset voltage and current operating point. A digging characteristic is obtained by increasing the reference current rapidly when the arc voltage (length) goes below a preset value. An intermittent spray transfer welding process, particularly applicable to continuous wire feed electrode systems, is created by maintaining the welding current at a high constant value until the electrode wire burns back to a maximum desired length (voltage) and then automatically reducing the current to a low constant value until the electrode is advanced sufficiently to shorten the arc and signal the system to change to a high current, etc.

Robert L Risberg

Papers

Adaptive control for arc welding