초록 ▼

Improved shock and electrical-fire protection circuits provide line-to-ground plus “line-to-line”fault protection in a power system, and monitor conditions after protective interruption to safely provide automatic restoration of current when the fault is cleared. Both full-wave and half-wave circuit

Improved shock and electrical-fire protection circuits provide line-to-ground plus “line-to-line”fault protection in a power system, and monitor conditions after protective interruption to safely provide automatic restoration of current when the fault is cleared. Both full-wave and half-wave circuits employ less expensive component combinations, including rectifiers and electromagnetic relays, to carry and switch load current. Protection is provided against the possibility of semi-conductor failure and the hazards associated with severed power conductors. A specialized resistance network fault detector for sensitizing enclosures, a hybrid zero sequence current transformer system and polyphase supply provide additional features.

대표청구항 ▼

In a power system the combination comprising a load and a first current blocking means connected in series to said load for passing substantial current in one direction through said load and passing substantially less current in the opposite direction, and a supply circuit connected to said load and

In a power system the combination comprising a load and a first current blocking means connected in series to said load for passing substantial current in one direction through said load and passing substantially less current in the opposite direction, and a supply circuit connected to said load and adapted to connect said load to an alternating current source, said supply circuit including a second current blocking means for passing substantial current in said one direction through said load and passing substantially less current in said opposite direction, said supply circuit having a load current relay connected between said alternating current source and said load for supplying said substantial current from the alternating current source to load in said one direction through said first and second current blocking means, said supply circuit further including a unidirectionally triggered switching means connected between said alternating current source and said load for receiving current in a direction opposite to said one direction and connected between said alternating current source and said load current switching means to supply actuating current in said one direction to said load current relay, said load current relay being controlled by current from said unidirectionally triggered switching means, said supply circuit further including control means operatively connected in parallel to said undirectioinally triggered switching means for activating and deactivating said undirectionally triggered switching means and substantially reducing said actuating current to said load current relay through said undirectionally triggered switching means and substantially reducing said substantial current in said one direction supplied by said load current relay whenever a load providing current flow in said opposite direction is connected to said supply circuit.