Square D Company

Thomas W Porter

Ronald L Farrington

Craig G Ross, Jr

A circuit breaker system uses a microprocessor for calculating at least one function of a measured current flow. The microprocessor provides other functions such as serial data stream communications, the ability of many circuit breaker systems to communicate with a central computer, storage of trip information concerning the last trip, storage of historical trip information concerning a number of past tips, EEPROM memory for storing trip information, the microprocessor may inhibit tripping on a high current fault to permit storage of trip information into a memory, power is derived from current transformers drawing energy from current flow to a load and the electronics are protected from high voltage caused by heavy current flow to the load, optical isolators are used for the circuit breaker to communicate with external equipment, a multi-turn resistor adjusts an external test voltage for testing the circuit breaker system, in the event that there is no load or a load drawing insufficient current to provide power for the electronics the circuit breaker may be externally powered to provide readout of electrically erasable programmable read only memory, the microprocessor reads setting switches and a multiplier plug. Also the microprocessor is capable of digitizing selected quantities frequently and of digitizing other quantities less frequently. A second microprocessor permits one microprocessor to sample voltage and current rapidly for metering purposes, and the second microprocessor operates other functions.

Computer-based metering arrangement including a circuit interrupter

A circuit breaker system employs a sensor circuit to measure the current flow in a conductor. A microcomputer monitors the current flow and trips a circuit breaker if the measured current flow exhibits certain predetermined characteristics. A power supply circuit generates a regulated output voltage proportional to the measured current flow to supply power to a portion of the circuit breaker system electronics. To protect the portion of the electronics powered by the power supply circuit, the output from the power supply is shorted through a resistance circuit for a predetermined period of time if the magnitude of the measured current flow induces an output voltage in excess of a predetermined level.

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Clearwater, FL, United States of America

Thomas W Porter