Abstract: A method of initializing short time and groundfault protection heat index accumulators to compensate for current flow during the time interval between the application of phase current and application of current measurement and protection algorithms in an electronic trip unit is presented. The electronic trip unit includes a microcontroller and associated ROM having trip unit application code, e.g., main functionality firmware, including initializing parameters, and boot code, stored therein and EEPROM having operational parameter code, e.g., encoded enumerations for parameters such as 50/60 Hz., UL/ANSI/IEC, etc., stored therein. The time internal comprises first and second time components.

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: A ground fault/rating plug for molded case circuit breakers is inserted within the circuit breaker cover for electrical connection with the circuit breaker electronic trip unit. A rating resistor within the ground fault/rating plug enclosure sets the circuit breaker ampere rating. Rotary switches on the outer surface of the ground fault/rating plug enclosure configures the trip unit for ground fault protection.

Abstract: A circuit breaker trip unit enclosure is adapted to receive rotary knobs that are limited in rotation in proportion to the circuit breaker short circuit rating. The externally-accessible rotary knobs extend within the enclosure to contact with a potentiometer affixed to the circuit breaker trip unit printed circuit board. A stop member is inserted within the enclosure access opening to detent the rotary knob shank that extends through the access opening.

Abstract: Each pole of a multi-pole circuit breaker is equipped to individually separate the circuit breaker contacts within each pole upon overcurrent occurrence. A digital processor within the circuit breaker trip unit determines the occurrence of zero current crossing of phase current within the individual poles and initiates contact separation at zero current values.

Abstract: This invention relates to a high ampere-rated circuit breaker which meets the electrical code requirements of the world market. The circuit breaker electronic trip unit is contained within a recess in the circuit breaker cover and is interlocked with the circuit breaker operating mechanism to articulate the operating mechanism upon removal. The accessory units are contained within an adjoining accessory compartment recess within the circuit breaker cover. Rejection pins on the accessories insure that the correct accessories are connected within the corresponding accessory compartments.

Abstract: An integrated circuit breaker is described having undervoltage trip capability along with automatic overcurrent protection. The undervoltage accessory further provides auxiliary power to the trip unit and allows the trip unit to report and record the undervoltage release operation.

Abstract: A combined bell alarm and lock-out accessory is connected with the electronic trip unit that controls a high ampere rated circuit breaker. The accessory interacts with the circuit breaker operating mechanism to activate the bell alarm upon circuit interruption and to prevent the closing of the circuit breaker contacts until the accessory is manually reset.

Abstract: An integrated circuit breaker having several accessory functions along with automatic overcurrent protection, allows selection between the various accessory functions in different combinations. Separate switches are arranged on the circuit breaker to allow factory as well as field selection of the accessory function combinations.

Abstract: A digital circuit interrupter utilizing current transformers for operating power is provided with a re-chargeable battery to power-up the trip unit as well as to power the display after an overcurrent trip occurrence to enable an operator to determine both the magnitude as well as the cause of the overcurrent condition.