Sealing technology is a critical design element in high-voltage DC contactors, directly influencing electrical performance, thermal capability, environmental resistance, and long-term reliability. This application note compares the two dominant approaches, epoxy (resin-based) sealing and ceramic (hermetic) sealing, and explains how each defines the internal gas environment and dielectric isolation under which switching occurs. Because the sealing method shapes contact resistance, arc extinction behavior, thermal limits, and lifecycle performance, the two technologies differ significantly despite serving the same fundamental purpose. The goal is to help engineers select the most appropriate sealing technology based on their application requirements.
