Circuit breaker with improved magnetic trip assembly

A circuit breaker for responding to abnormal currents in a conductor in an electrical system, said circuit breaker comprising:

• electrical contacts operable between a closed position in which a circuit is completed through said conductor and an open position in which said circuit through said conductor is interrupted;
• a latchable operating mechanism operable to open said electrical contacts when unlatched;
• a trip bar rotatable from a biased position to a trip position to unlatch said operating mechanism;
• and
• a magnetic trip assembly comprising:
• a stationary magnetic structure;
• a movable armature which is attracted to said stationary magnetic structure by an abnormal current through said conductor to rotate said trip bar to said trip position;
• and
• plate means mounted to said movable armature and disposed between said movable armature and said stationary magnetic structure to adjust the amount of said abnormal current required to attract said movable armature to said stationary magnetic structure and in turn rotate said trip bar to said trip position.