Better Interpretation of Vacuum Interrupter Test

At one vacuum interrupter (VI) manufacturing facility, a single-phase, high-power circuit is used to evaluate the performance and quality of Vis, and to simulate certification tests. Precertification testing of Vis provides a great cost saving to manufacturers of vacuum circuit breakers in their development process, because it allows a them to bring new breaker models to a certification laboratory with a high degree of confidence that the breaker Vis can perform well at the targeted rating. A parallel stage in the advanced development of new VI designs involves fundamental investigations of the effects of high-current vacuum arcs on the internal components of the arcing chamber. At this level, an experimental vacuum system is used for high-speed photography of vacuum arcs between VI powder-metallurgy contacts in a demountable chamber. In this article, we step through this development process, from fundamental investigations of the arc-contact interaction to performance and precertification testing of manufactured Vis. We also describe how VI models are tested above their rated current to monitor the quality of their materials and processing.