Replaceable solid state trip unit

摘要

A molded case multi-pole circuit breaker is provided with a removable and replaceable solid state trip unit constructed with all fault current detecting elements within a common housing. For each circuit breaker pole the trip unit includes an input and an output transformer feeding circuitry mounted on a board disposed within the common housing. The circuitry output is connected to operate a permanent magnet latch for release of a mechanical latch that normally holds the contact operating mechanism in a reset position.