Development of Contact Material Solutions for Low-Voltage Circuit Breaker Applications

The focus of the studies is on the influence of contact material production parameters, and the contact material breaker interaction of material combinations used for low voltage protection devices. The influence of the magnetic blast field and the material composition on erosion behavior and contact resistance of AgW materials will be scrutinized by model-switch tests. Especially the mass loss during break operation is heavily influenced by the applied magnetic flux density. Furthermore the switching performance of AgC materials with different manufacturing parameters and fiber orientation will be compared. The improved erosion rate of optimized AgWCC materials in comparison to AgC during electrical lifetime test will also be pointed out. The paper represents a guideline for material selection and problem solving during protection device design by comparing the varying contact material behavior under different types of loads.