A Switchgear Manufacture's Perspective of Contact Material Re-quirements

Inhalt:
In modern switchgear the contact material has become more important for the performance-to-cost ratio than in many years before. Especially with increasing functionality, smaller installation size, and higher ratings, the contact system is the one of the major innovation drivers in switchgear development. In this contribution the requirements for contacts from a switchgear manufacturer’s perspective is described. Starting from the several operational modes - nominal operation, make and break, short circuit - we explain the demands from a physical point of view and derive the specific requirements of the contact material and the contact system. The first step for the "optimal" contact system is a well-balanced combination of the characteristics of the contact material in regard to the application of the switchgear. The second step is to use appropriate manufacturing processes to enable the realization of the requirements needed, always in regard to the application, which puts additional constraints to a proper contact material selection.