Abstract: A modular slot motor assembly and arc plate assembly combination for a circuit breaker is disclosed. The modular slot motor assembly is positioned proximate the arc plate assembly by lockingly securing it to a subcomponent housing in order to better provide an enhanced separation of the contact arms. During a short circuit event the modular slot motor assembly provides added acceleration to a moving contact arm. To protect the modular slot motor assembly from damage, an insulating casing is applied to at least a portion of the modular slot motor assembly.

Abstract: Methods, apparatus, and systems are provided for a selectivity device for a circuit breaker. The invention includes a modular assembly adapted to be coupled to a load conductor assembly. The modular assembly includes a tripping plunger including a cam surface adapted to interact with a breaker tripping mechanism; an armature coupled to the tripping plunger; a yoke adapted to generate a magnetic field in response to an electric current in the load conductor assembly and disposed to apply a magnetic force proportionate to the electric current on the armature; and a spring assembly adapted to counter-balance the magnetic force up to a predefined tripping current in the load conductor assembly. Numerous additional aspects are disclosed.

Abstract: A slot motor apparatus for a circuit breaker is disclosed. The slot motor has first and second legs connected by a thin web, and an extending portion extending rearward from the rear faces of the legs. Slot motor-arc plate assemblies having an arc plate assembly received at least partially overtop of the extending portion are also disclosed, as are assemblies having the arc plate assembly received very close to the rear faces of the slot motor legs. Circuit breakers, slot motor-arc plate assemblies, slot motor covers, and methods of operating the slot motor-arc plate assemblies are disclosed, as are other aspects.

Abstract: An autotrip plunger of a circuit breaker is disclosed for opening contacts of the circuit breaker to install and uninstall the circuit breaker from a current source. In an embodiment, the autotrip plunger includes a compression spring, a first body section and a second body section, the first body section including a contact surface for contacting a tripping element of the circuit breaker and the second body section including an arbor shaft for fitting in the compression spring. At the free end of the arbor shaft, the arbor shaft includes at least one radial protrusion for holding the compression spring. A circuit breaker with such an autotrip plunger is also disclosed.

Abstract: Methods, apparatus, and systems are provided for a selectivity device for a circuit breaker. The invention includes a modular assembly adapted to be coupled to a load conductor assembly. The modular assembly includes a tripping plunger including a cam surface adapted to interact with a breaker tripping mechanism; an armature coupled to the tripping plunger; a yoke adapted to generate a magnetic field in response to an electric current in the load conductor assembly and disposed to apply a magnetic force proportionate to the electric current on the armature; and a spring assembly adapted to counter-balance the magnetic force up to a predefined tripping current in the load conductor assembly. Numerous additional aspects are disclosed.

Abstract: A slot motor apparatus for a circuit breaker is disclosed. The slot motor has first and second legs connected by a thin web, and an extending portion extending rearward from the rear faces of the legs. Slot motor-arc plate assemblies having an arc plate assembly received at least partially overtop of the extending portion are also disclosed, as are assemblies having the arc plate assembly received very close to the rear faces of the slot motor legs. Circuit breakers, slot motor-arc plate assemblies, slot motor covers, and methods of operating the slot motor-arc plate assemblies are disclosed, as are other aspects.

Abstract: An autotrip plunger of a circuit breaker is disclosed for opening contacts of the circuit breaker to install and uninstall the circuit breaker from a current source. In an embodiment, the autotrip plunger includes a compression spring, a first body section and a second body section, the first body section including a contact surface for contacting a tripping element of the circuit breaker and the second body section including an arbor shaft for fitting in the compression spring. At the free end of the arbor shaft, the arbor shaft includes at least one radial protrusion for holding the compression spring. A circuit breaker with such an autotrip plunger is also disclosed.