OVERCURRENT PROTECTION CIRCUIT

摘要

Circuit protection systems employing arrangements of PTC devices and mechanical switches. The PTC device is not involved in the circuit until a fault is sensed. In one embodiment, a current sensing relay senses an overcurrent and directs the current to the PTC device. As the voltage across the PTC device increases, a parallel arrangement of voltage sensing relays completes the operation of the protection system, and disconnects the load until the protection system is reset. The protection system may be reset manually or remotely.