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Abstract
The precise control of gas-tungsten and gas-metal arc welding processes by use of a high performance transistor power source is considered. The first part of this work is dedicated to development of a high efficiency class H power source with adjustable static and dynamic characteristics. A comparison is made of the properties of the class H power source with other approaches such as switching, SCR and conventional linear regulator designs.
A prototype class H power source is used to perform a series of test welds to establish the optimum steady-state and transient properties for use with gas-metal arc welding. Two methods are used to modify the transient behavior of the power source. The first pre-conditions the control input to the power supply as a function of the instantaneous output voltage. The second method modifies the transient properties by inclusion of a differentiator in the current feedback loop of the power source.
A theoretical analysis is presented showing the effect of high frequency pulsing on the temperatures and pressure in the gas-tungsten arc. Visual and acoustic observations are made to confirm the results of the analysis.
