Abstract: A circuit breaker racking system includes an electrical drive operatively connected to a mechanical racking mechanism that carries the circuit breaker and moves the circuit breaker between a connect position and a disconnect position within a cubicle, and a circuit breaker trip unit that receives remote commands and controls the electrical drive based on the remote commands. A switchgear system including at least one circuit breaker with an integrated auto-racking system is also provided.

Abstract: A circuit breaker trip unit includes an input section receiving a phase current level signal. A processor is in communication with the input section and generates a first trip signal based on the phase current level signal and user-adjustable trip settings. The trip settings include long time and short time pickup and delay settings. An analog instantaneous trip circuit is in communication with both of the input section and the processor. The analog instantaneous trip circuit includes a digital potentiometer having a non-volatile memory. The potentiometer provides a reference signal corresponding to a resistance setting stored in the memory. The analog instantaneous trip circuit compares the phase current level and reference signals, and generates a second trip signal based on a result of the comparing. The processor programs the resistance setting stored in the memory according to a user-adjustable instantaneous current pickup setting.

Abstract: A circuit breaker trip unit includes an input section receiving a phase current level signal. A processor is in communication with the input section and generates a first trip signal based on the phase current level signal and user-adjustable trip settings. The trip settings include long time and short time pickup and delay settings. An analog instantaneous trip circuit is in communication with both of the input section and the processor. The analog instantaneous trip circuit includes a digital potentiometer having a non-volatile memory. The potentiometer provides a reference signal corresponding to a resistance setting stored in the memory. The analog instantaneous trip circuit compares the phase current level and reference signals, and generates a second trip signal based on a result of the comparing. The processor programs the resistance setting stored in the memory according to a user-adjustable instantaneous current pickup setting.

Abstract: A circuit protection system has a normal mode, and a maintenance mode with reduced potential arc flash energy. A downstream circuit breaker is mounted within a first enclosure comprising a first access panel. A locking mechanism locks the first access panel closed. An upstream breaker is mounted within a second enclosure comprising a second access panel. A current sensor senses current and is in communication with an electronic trip unit that controls current interruptions by the upstream breaker based on a trip setting. A user interface device is accessible when second enclosure is closed, and allows user selections of normal and maintenance modes. When maintenance mode is selected, the trip unit changes the trip setting such that potential arc flash energy is reduced. The system is configured to keep the first access panel locked closed based on normal mode being selected, and allow unlocking based on maintenance mode being selected.

Abstract: A zone-selective-interlocking system for an electrical power distribution system that has at least one upstream breaker and at least one downstream breaker is provided. Each breaker in the power distribution system has a zone-selective-interlocking circuit that includes a zone-selective-interlocking-input circuit and a zone-selective-output circuit. The zone-selective-interlocking system also includes a monitoring device to monitor the voltage sent from the zone-selective-interlocking-output circuit of the at least one downstream breaker to the zone-selective-interlocking-input circuit of the at least one upstream breaker and determine whether there is a proper or improper connection between the upstream and downstream breaker and whether the downstream breaker is sending a restraint signal to the upstream breaker.