INCREASING THE EFFICIENCY OF THE POWER SOURCE SYSTEM – PLASMATRON AND ITS ENERGY PARAMETERS

The engineering method for calculating the parameters of the power supply system-the plasma torch-is considered, which makes it possible to increase the stability of the power supply system plasmatron by reducing the magnitude of the disturbance of the arc current for random small changes in the voltage of the power source. The influence of large-scale current pulsations in plasma torches for spraying and surfacing on the heating efficiency of sprayed and surfacing powders and their dependence on the parameters of the “power source-plasma torch” system has been revealed. The proposed method for calculating the parameters of the plasma torch power system allows increasing the stability of the “power source-plasma torch” system by reducing the magnitude of arc current perturbations during random small changes in the power source voltage. The obtained analytical dependencies allow calculating the electrical, thermal and erosion characteristics of plasma torches for spraying, surfacing, welding and cutting, taking into account their dependence on the physical properties of the gas, the dimensions of the discharge channel, the change in current strength and the flow rate of the working gas. A mathematical model of the interaction of arc plasma with heated powder material has been further developed, which takes into account the mutual influence of the processed material on the parameters of the plasma jet. It is known that the nature of the distribution of erosion of the plasma torch electrodes corresponds to the linear current density of the arc. This indicates that erosion is determined mainly by large heat fluxes through the arc spots. Therefore, if you somehow influence the arc column and force it to change the place of attachment to the electrodes, that is, to distribute erosion more evenly along the length of the discharge channel, you can significantly increase the service life of the plasma torch. One of the ways to influence the arc column is to apply a disturbing alternating voltage to the DC arc. At the same time, by changing the values of the alternating component of the current and frequency, you can change the behavior of the arc column. Taking into account the fact that the influence of external electrical disturbances on the arc column can be another way to increase the service life of the plasma torch, as well as changing its output parameters (efficiency, temperature, jet length, etc.), we have made an attempt to obtain theoretical formulas for calculating thermal and electrical characteristics that can be used in engineering practice when designing plasma torches.