Metal-Sealed Gas-Protected Contacts

Contacts in telephone switching systems are used for two basic applications, either for switching functions or control functions, having quite different requirements. So it has been found practical when new gas-protected contacts were being developed by Siemens to have two types of contacts: a highly miniaturized make contact especially for use in crosspoint relays with a lifetime expectancy of about five million operations, and a larger contact for control relays capable of carrying a greater load, and designed as a make or a make-before-break contact which is expected to carry out one order of magnitude more operations. Both contacts are hermetically sealed in metal enclosures filled with an inert gas.