General properties of high current switching under 36 V DC for Ag and AgSnO2 contacts

This study presents a study concerning the contact opening under DC voltage in the case of high-intensity currents (a few hundred amperes) for Ag and AgSnO₂ contacts. The application fields are mainly automotive and aeronautical systems. An experimental device has been designed in order to study the opening of contacts under various conditions. The influence of several parameters (opening velocity, arc current intensity, nature of the circuit load and so on) on contact opening is studied. The measured parameters characterising the opening phase are: the arc duration, the arc energy and the arc voltage. Moreover, the study of the contact erosion under the electric arc action is achieved with the help of a 3D profilometer enabling the measurement of mass transfer and, for instance, of the amount of molten or eroded metal.