Abstract: A circuit breaker assembly having an electronic trip unit used to detect an overcurrent condition in a protected electrical circuit. The electronic trip unit being electrically connected to a current transformer used to sense electrical current and provide operating power to the electronic trip unit. The current transformer comprising a metal core having a top surface and a bottom surface where the difference between the top and bottom surfaces defines a height of the core. The core having a concentrical opening extending through the height so that the distance between an outside point on the concentrical opening and the closest outside point of the core defines a thickness of the core at that point. Passing through the core opening is a primary winding and encircling the thickness of the core is a secondary winding. To optimize usage of the current transformer, a partial air gap is added to the metal core so that the range of operation is maximized while at the same time minimizing the remanence attenuation.

Abstract: A circuit breaker assembly having an electronic trip unit used to detect an overcurrent condition in a protected electrical circuit. The electronic trip unit being electrically connected to a current transformer used to sense electrical current and provide operating power to the electronic trip unit. The current transformer comprising a metal core having a top surface and a bottom surface where the difference between the top and bottom surfaces defines a height of the core. The core having a concentrical opening extending through the height so that the distance between an outside point on the concentrical opening and the closest outside point of the core defines a thickness of the core at that point. Passing through the core opening is a primary winding and encircling the thickness of the core is a secondary winding. To optimize usage of the current transformer, a partial air gap is added to the metal core so that the range of operation is maximized while at the same time minimizing the remanence attenuation.

Abstract: A method for error detection and correction in an electronic trip unit is presented. The electronic trip unit includes a ROM having trip unit application code, e.g., main functionality firmware, including initializing parameters, and boot code, stored therein and an EEPROM having operational parameter code, e.g., encoded enumerations for parameters such as 50/60 Hz., UL/ANSI/IEC, ect., stored therein The integrity of the code is monitored using CRC or checksum. Corrupted data is recovered by using encoded enumerations with at least two repetitive bit patterns of appropriate width. Encoding enumerations with greater that two repetitive bit patterns allows for each enumerated value to be recovered from any single bit corruption by replacing the corrupted pattern with the matching pattern. Alternatively, with a plurality of encoded enumeration groups stored in the EEPROM a corrupted enumeration can be properly selected and corrected by cross correlating the enumeration groups.

Abstract: The idea behind this algorithm is to provide prioritized data in an optimal sequence to expedite initialization/activation of ordered processes necessary to effect circuit protection functionality from a circuit breaker trip unit.

Abstract: An electronic circuit interrupter includes an electronic trip circuit contained within a circuit interrupter enclosure along with an externally accessible rating plug for setting the ampere rating. The rating plug includes keying tabs that fit within corresponding keying slots formed on the top surface of the electronic circuit interrupter enclosure. Interlock is provided between the rating plug and the electric panelboard which includes a plurality of electronic circuit interrupters connected within an industrial power system. Tabs formed on the side walls of the rating plug are trapped under the panelboard face plate to prevent removal of the rating plug without first removing the panelboard face plate.

Abstract: An integrated protection unit is a circuit breaker which includes basic overcurrent protection facility along with selective electrical accessories. A molded plastic accessory access cover secured to the integrated protection unit cover protects the accessory components contained within the circuit breaker cover from the environment. A shunt trip unit is one such accessory component which can be field-installed without affecting the integrity of the circuit breaker overcurrent protection components.

Abstract: The overcurrent trip levels of an electronic circuit breaker are selected by means of a variable resistance ladder network comprising binary encoded switches. The binary encoded switches reduce the size and cost of the trip unit, rendering electronic trip facility to a wider range of industrial circuit breakers utilizing both analog as well as digital processing circuits.