MODELING OF ENERGY-TRANSPORT IN ARCING ELECTRICAL CONTACTS TO DETERMINE MASS-LOSS

This paper presents a model which calculates the amount of erosion of an electrical contact undergoing arcing for a range of contact opening conditions. The model assumes all vaporized material is lost from the contact and that the material lost is related to the energy received by the contact, It is proposed that two processes occur which transpor t energy to the contact surface from the are discharge. These have bee n called the radial transport process and the channeled transport proc ess. Calculations at different ratios of the transport processes are c ompared to experimental data at 9 A, 64 V DC. The modeling procedure c onsists of several stages: 1) the are discharge is divided into three regions which generates energy for dissipation; 2) the energy from eac h region is dissipated through the are and delivered to the contact su rface by radial/channeling transport processes; 3) heat flow through t he contact from the surface is calculated using an explicit numerical finite difference scheme dependant upon energy input, contact dimensio ns, and material properties. This is then used to determine the temper ature gradient of the surface and any phase changes; 4) knowing the co ndition of the contact surface, and contact separation, the mass loss is calculated assuming all evaporated material is removed from the sur face.