This paper investigates the dynamic behavior of Gas Metal Arc Welding (GMAW) process for two types of power supplies-inverter and rectifier-for short circuit transfer mode. The large ripples on the rectifier power source are able to perturb the metal transfer mode. In this experimental work some operating points in the short circuit mode have been selected using an automatic pipeline welding system, and the effects of both rectifier and inverter effects (as the power supplies) on the process have been illustrated. For small voltage and currents, the two power supplies effects are similar in the short circuit transfer mode. On the other hand, for larger voltage and current values, the responses will be different as the rectifier power supply produces more perturbations on the metal transfer. However, the process with the inverter has a more regular behavior and a more stable detachment.
