Medium-voltage circuit-breaker

A fast acting switching mechanism for a circuit breaker, said fast acting switching mechanism comprising:

• a drive rod articulated to a drive module and supporting at an end thereof a contact bridge having at opposite ends thereof respective moveable contacts for switchably engaging a pair of fixed contacts of the circuit breaker;
• a contact spring unit operatively coupled to the drive module configured to apply a closing pressure;
• and
• a latch configured to latch the drive rod in an open or closed position after operation of the circuit breaker and to prevent rebounds, wherein the contact bridge comprises:
• a pair of side conductors supporting on upper edges thereof an armature having an exposed upper surface that supports said moveable contacts at opposite ends of the armature;
• and
• a reinforcing element inserted between the side conductors, such that when current flows through the contact bridge, corresponding magnetic fluxes generated by the side elements cancel each other in an area between the side elements, whereby substantially no magnetic flux passes through the reinforcing element.