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 the breaking Ag contacts. The parameters which were taken in this experiment were the whole arc duration (metallic phase arc duration plus gaseous phase one), metallic phase arc duration, contact resistance, bridge energy, and the electrode material mass change. Some experiments were performed under the various conditions of air pressure and contact current. From the results obtained through the process of arc duration and contact resistance, we 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 condition, which led us to the conclusion that the electrode material mass change was closely related to the metallic phase arc discharge.