Influence of Ageing on Electrothermal Condition of Low Current Contact

Electrical contacts’ main function is to close an electrical circuit securely transporting current throughout the contact surface. Electrical contacts range from high, medium to low current depending on their usage. Power transmitting electrical contacts are expected to transmit a current of a significant intensity whereas the signal transmitting electrical contacts usually transmit low currents. However, electrical contacts undergo gradual change at the interface due to the action of temperature, corrosion, mechanical discontinuities induced by vibration etc. all these disturbing factors lead to the aging and degradation of the contact. In some cases where the contact resistance increases due to electrical loses, the local temperature may increase, thereby accelerating contact degradation. This paper presents a numerical analysis on the variation of temperature of a simple low current contact model having a thin oxide film layer at the interface which serves as the ageing factor using finite element method (FEM) in COMSOL Multiphysics.