Abstract: An adjustable magnetic trip unit for a circuit breaker includes a torsion spring which applies a bias force to the plunger of a trip solenoid. The torsion spring is mounted on a driven bevel gear and wound by an adjustment knob coupled to a driving bevel gear to adjust the current at which the solenoid is activated. An indexer having peripheral flats which engage a seat in the circuit breaker housing provides a plurality of discrete positions of the adjustment knob. Depressing the adjustment knob against a second spring unseats the indexer for rotation of the adjustment knob between settings. In addition, a slide with an inclined surface bearing against the plunger and coupled to the driven bevel gear, provides simultaneous adjustment of plunger gap with adjustment of the torsion spring force to increase the range of adjustment.

Abstract: An adjustable magnetic trip unit for a circuit breaker includes a torsion spring which applies a bias force to the plunger of a trip solenoid. The torsion spring is mounted on a driven bevel gear and wound by an adjustment knob coupled to a driving bevel gear to adjust the current at which the solenoid is activated. An indexer having peripheral flats which engage a seat in the circuit breaker housing provides a plurality of discrete positions of the adjustment knob. Depressing the adjustment knob against a second spring unseats the indexer for rotation of the adjustment knob between settings. In addition, a slide with an inclined surface bearing against the plunger and coupled to the driven bevel gear, provides simultaneous adjustment of plunger gap with adjustment of the torsion spring force to increase the range of adjustment.

Abstract: A circuit interrupter including a housing, separable main contacts within the housing, and an operating mechanism within the housing and interconnected with the separable main contacts. A trip mechanism is disposed within the housing that includes a trip bar assembly rotatable about an axis and that, when rotated, generates a tripping operation causing the operating mechanism to open the contacts. The trip bar assembly includes a trip member translatable along the axis. The trip mechanism includes a tripping actuator movable along a predetermined path of travel as a function of electrical current. The tripping actuator contacts a contact area of the trip member at a predetermined location along the predetermined path of travel of the tripping actuator and causes the trip bar assembly to rotate and generate the tripping operation upon a predetermined current threshold.

Abstract: An adjustable magnetic trip device for a molded case circuit breaker is provided where the trip device includes a plunger and a stationary core as well as a plunger support structure with a movable plunger carriage. The position of the plunger assembly and carriage relative to the stationary core is determined by a cam assembly having a body with a plurality of sections, each section having a different radius. The plunger carriage is responsive to rotation of said cam assembly and may be adjusted by rotating the cam. The over-current condition for the trip device is a function of the distance between the plunger assembly and the stationary core. Accordingly, the over-current condition may be changed by rotating the cam. As each section of the cam has a constant radius, the over-current condition remains the same no matter where the carriage contacts a certain section of the cam.

Abstract: A circuit interrupter including a housing, separable main contacts within the housing, and an operating mechanism within the housing and interconnected with the contacts. An arc extinguisher assembly is disposed within the housing. Also provided within the housing is a slot motor assembly having a cavity region within which the contacts are substantially located. The slot motor assembly electro-magnetically interacts with current flowing between the contacts, and includes magnetic plates positioned in a slot motor housing. The slot motor housing has a tendency to move an arc existing between the contacts toward the arc extinguisher assembly. The slot motor assembly also includes an insulation member positioned within the cavity region and between the magnetic plates and the slot motor housing.