Circuit breaker with overcurrent trip test switch - has additional connections to permit use as remote trip

摘要

The circuit breaker has an overcurrent trip, and an overcurrent trip test circuit. It may be opened from a remote point without the necessity of a separate trip coil. The contacts (12a, 12b) of the trip test switch (12) are brought out to additional terminals (12', 12"). This allows them to be connected (15) to a remote control centre in which there is a switch (16) for bridging the contacts. The trip test is typically connected between one phase and neutral, with a limiting resistor in series in order to produce a simulated overload current. A further advantage is that the circuit breaker cannot be reclosed until the overload trip has been reset. It can thus also be used as a lock out to prevent unauthorized reclosure.