On the dynamics of cutting arc plasmas: the role of the power supply ripple

LEANDRO PREVOSTO; BEATRIZ MANCINELLI; HÉCTOR KELLY

ADVANCED ELECTROMAGNETICS

AEM

Año: 2012 vol. 1 p. 12 - 15

2119-0275

The power sources used in cutting arc torches are usually poorly stabilized and have a large ripple factor. The strong oscillatory components in the voltage and arc current produce in turn, large fluctuations in the plasma quantities. Experimental observations on the dynamics of the non-equilibrium plasma inside the nozzle of a 30 A oxygen cutting torch with a 7 % ripple level of its power source are reported in this work. The observed electron temperature (mean value = 5400 K) shows a rms deviation of 5 % (= 300 K), which is of the order of the arc voltage ripple level. A considerable different situation occurs with the plasma density (mean value = 3 x 10^19 m^-3). In this case the rms deviation was 75 %, much greater than that of the electron temperature.