Adjustable magnetic trip assembly for circuit breaker

1. Field of the Invention 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.