Role of the metallic phase arc discharge on arc erosion in Ag contacts

The influence of a metallic-phase arc discharge on contact phenomena was experimentally studied in breaking Ag contacts. The parameters that were measured were the total arc duration (metallic phase plus gaseous phase), metallic-phase arc duration, contact resistance, bridge energy, and electrode material loss. Some experiments were performed for various air pressures and contact currents. It was found that the contact resistance was low in the metallic-phase arc region, and high and almost constant in the gaseous-phase arc region. The relationship between material loss and transfer and the accumulated metallic-phase arc duration was log-proportional, irrespective of air pressure, which led the authors to the conclusion that the electrode material loss is closely related to the metallic-phase discharge duration