Abstract: A multiphase circuit breaker has a magnetic trip assembly which includes an adjusting bar slidable longitudinally to simultaneously adjust the bias applied by individual torsion springs to the rotatable armature of the magnetic trip assembly for each pole over a range of trip currents from a high setting to a low setting. Adjusting screws carried by the adjusting bar provide for adjustment of the gap between the armature and stationary magnetic structure independently at the high and low settings separately for each pole. An additional set of adjusting screws can be inserted in the adjusting bar to provide a single adjustment of the gap over the full range of spring bias settings.

Abstract: A draw out interlock comprises an elongated interlock member which is coupled to the manual trip mechanism of a circuit breaker. The interlock member is springed bias to an extended position where it projects through the back wall of the circuit, but is retained in a retracted position by the surface against which the circuit breaker is mounted. As the circuit breaker is removed from the mounting surface, the interlock member extends actuating the manual trip mechanism and interrupting current before the circuit breaker becomes disconnected from the protected conductor to prevent arcing at the disconnects.