Circuit interrupter

A multi-pole circuit interrupter, comprising:

• a pair of movable and stationary contact arms for each pole each having at its one end a contact;
• a contact cross bar carrying said movable contact arm in common to all the poles and movable between contact closing and opening positions;
• a contact spring means for providing a contacting pressure between the contacts in the closed position;
• an operating mechanism for unitarily operating said movable contact arm and said contact cross bar;
• a trip mechanism for causing said operating mechanism to collapse in response to a trip command irrespective of its position;
• a time limiting trip bimetal element operable in response to an overcurrent to actuate said trip mechanism;
• arc extinguishing means for extinguishing an electric arc established between separated contacts;
• an insulating casing enclosing at least live portions of the interrupter less terminals for the external connection and having therein an arc exhaust port;
• an electromagnetic means including a magnetic core, at least two separate magnetic yokes each extending from said magnetic core to provide a magnetic gap therebetween, and a primary and a secondary coil, said primary coil being wound around said magnetic core and electrically serially connected to said contact to flow a primary current therethrough and said secondary coil being wound around said magnetic core in an inductive relationship with said primary coil and electrically serially connected to said bimetal element to cause a secondary current to flow in said bimetal element, thereby forming a current transformer;
• means, including portions of said electromagnetic means and the movable contact arm disposed in said magnetic gap, for driving said movable contact arm into the contact open position due to an electromagnetic force exerted on said contact arm by the magnetic flux generated in said magnetic gap upon the occurrence of a short-circuit current;
• means including portions of said magnetic core means for magnetically driving an electric arc established between separated contacts by a magnetic field formed within said magnetic gap;
• and
• an instantaneous trip means including a magnetic armature disposed in said magnetic gap and capable of being magnetically actuated by a magnetic field in said magnetic gap upon the occurrence of a predetermined overcurrent to provide the trip command to said trip mechanism.