Molded case circuit breaker with improved high fault current interruption capability

A circuit breaker comprising, in combination:

• an insulating housing;
• elongated stationary contact support means disposed in said housing and having a stationary contact at one end;
• a movable contact carrier rotatably supported in said housing;
• an elongated movable contact arm attached to said carrier for pivotal movement relative to said carrier and having a moveable contact at one end;
• means biasing said movable contact arm for integral rotary movement with said carrier;
• operating means for manually operating said carrier to open and closed positions, said movable contact arm being disposed substantially parallel to and co-extensive with said stationary contact support means in the closed position;
• means connecting said stationary contact support means and said movable contact arm in an electric circuit for effecting current flow in opposite directions therein when said contacts are in said closed position wherein currents in said stationary contact support means and said movable contact arm greater than a predetermined value generate electromagnetic forces for effecting pivoting movement of said movable contact arm relative to said carrier and away from said stationary contact support means for separating said contacts;
• and
• flux amplifier means forming a magnetically closed loop around said stationary contact support means and said movable contact arm for amplifying said electromagnetic forces.