Study on voltage characteristics of short air arc with high current density arc root

In this paper, the voltage characteristics of short air arc with high average current density arc root were studied at atmospheric pressure. Cu-W electrodes with diameter of 5-14mm and gap length of 0.2-3 mm were used in the experimental study. The experimental current varies from 1,000A to 16,600 A. The average current density of the arc roots in the experiment was up to 245 A/mm2. In the scope of this study, the arc voltage is a function of the average current density of arc root when the electrode gap length is fixed. For same average current density of arc root, the arc voltage is approximately the same even if the experimental currents are different. And the arc voltage increases with the increment of the average current density of arc root. Theoretical analysis and experimental results show that the electrode fall voltage almost doesn’t change with the average current density of arc root. However the arc column voltage increases with the increment of the average current density of arc root.