Current limiting circuit breaker with improved magnetic drive device

A current limiting circuit interrupter, comprising:

• a housing;
• separable contacts supported within said housing;
• a slotted magnetic drive device mounted within said housing and having a slot with an open end and a closed end;
• and
• an elongated movable contact arm supporting one of said contacts and supplying current thereto, said contact arm being transversely disposed in said slot so that current flow through said contact arm is in a direction generally perpendicular to a line connecting said open and closed slot ends, said contact arm being movable between a first position at said slot open end which permits current flow through said contacts and a second position at said slot closed end which interrupts current flow through said contacts, overcurrent conditions through said contacts generating magnetic flux in said magnetic drive device across said slot open end to generate an electro-dynamic force driving said contact arm from said first position to said second position;
• said magnetic drive device comprising a saturable magnetic member bridging the open end of said slot and shunting magnetic flux produced across said slot open end, said magnetic member saturating at a predetermined overcurrent value to raise to said predetermined value the threshold at which said electro-dynamic force is produced.