An electromagnetic trip unit, wherein: the electromagnetic trip unit includes a movable core, an upper static core and a lower static core; the movable core can move relative to the upper static core and the lower static core in the upper static core and the lower static core; a movable core body end of a movable core body of the movable core faces and approaches the lower static core end of the lower static core, when the electromagnetic trip unit is not released, a first magnetic field air gap is formed between the movable core body end and the lower static core end; the movable core body of the movable core is also provided with a movable core body step, when the electromagnetic trip unit is not released, a second magnetic field air gap is formed between the movable core body step and the lower static core end.

An ultra-fast moving conductor for use with a circuit breaker is provided. The moving conductor includes a hollow outer stem and a removable core. Multiple removable cores are produced for use with the moving conductor for different purposes. The outer stem is produced from annealed copper that must be brazed before the circuit breaker is placed into operation, and a first removable core produced from copper is inserted into the outer stem to provide structural reinforcement to the outer stem during brazing. After brazing is complete, the copper core is removed from the outer stem, and a significantly lighter work hardened aluminum core is inserted into the outer stem. The lightweight aluminum core enables the moving conductor to open the circuit breaker much faster than the copper core would, and the copper core prevents contamination of the brazing furnace that would result from using the aluminum core during brazing.

An ultra-fast moving conductor for use with a circuit breaker is provided. The moving conductor includes a hollow outer stem and a removable core. Multiple removable cores are produced for use with the moving conductor for different purposes. The outer stem is produced from annealed copper that must be brazed before the circuit breaker is placed into operation, and a first removable core produced from copper is inserted into the outer stem to provide structural reinforcement to the outer stem during brazing. After brazing is complete, the copper core is removed from the outer stem, and a significantly lighter work hardened aluminum core is inserted into the outer stem. The lightweight aluminum core enables the moving conductor to open the circuit breaker much faster than the copper core would, and the copper core prevents contamination of the brazing furnace that would result from using the aluminum core during brazing.

An electromagnetic trip unit, wherein: the electromagnetic trip unit includes a movable core, an upper static core and a lower static core; the movable core can move relative to the upper static core and the lower static core in the upper static core and the lower static core; a movable core body end of a movable core body of the movable core faces and approaches the lower static core end of the lower static core, when the electromagnetic trip unit is not released, a first magnetic field air gap is formed between the movable core body end and the lower static core end; the movable core body of the movable core is also provided with a movable core body step, when the electromagnetic trip unit is not released, a second magnetic field air gap is formed between the movable core body step and the lower static core end.

A switching-device tripping apparatus for a switching device includes contact pieces that can be moved relative to one another. Relative motion between the contact pieces is generated by a gear or transmission configuration. The gear or transmission configuration has a pawl in order to control motion of the contact pieces relative to each other. First and second tripping devices are provided, which work or operate the same pawl and drive the same pawl.