Analytical and Experimental Investigation of the Electrical-Thermal Behaviour of Electrical Contact Systems

Abstract

The current carrying capacity, which is determined by the electrical-thermal behaviour, is one of the main features of an electrical contact system. The purpose of this study is to develop an analytical model which describes the electrical-thermal behaviour of electrical contact systems. Established mechanical, electrical, thermal and contact physical relations are combined to design the analytical model. Differential equations with appropriate boundary conditions are used to solve the heating problem. The various parts of an electrical connector represent separate subsystems. The geometry, the material properties and the heat transfer coefficients for the contact system, the terminal clamp and the wire have been taken into account. These different subsystems have been connected to obtain the overall temperature distribution. In order to verify the analytical model, contact systems made of three copper alloys with different electrical and thermal properties are investigated experimentally at various current loads. It was shown that the analytical model can predict the temperature rise for simple geometry well. Using the analytical model several parameters can be easily changed. Moreover, the main influencing factors and their relationships can be identified directly on the equations. Therefore, the physical - mathematical point of view of an analytical calculation can help to understand the model structure of a contact system.