Patent ID: 8890011

Claim:
A Medium Voltage circuit breaker comprising a pole assembly having, for each phase, an interruption chamber configured to house a first fixed contact and a second movable contact reciprocally couplable/uncouplable between an open and a closed position, said circuit breaker further comprises: an actuator to actuate the opening and closing operation of said circuit breaker said actuator being accommodated in a casing; a kinematic chain operatively connecting the actuator to at least said second movable contact; and an insulating base frame supporting said pole assembly and said actuator; wherein said insulating base frame comprises a base wall and first, second and third lateral walls, a plurality of fixing points being present in the volume defined by said base and lateral walls for fixing said pole assembly and said actuator to said insulating base frame; wherein said insulating base frame comprises a plurality of cavities passing through said base wall and a front portion obtained in said base wall and adjacent to said cavities; wherein said interruption chambers are positioned in correspondence of said cavities and are fixed to said base frame at said fixing points; wherein the casing of said actuator is positioned in correspondence of said front portion and is fixed to said base frame at said fixing points; wherein said kinematic chain is housed in said base frame in a position between said front portion and the cavities housing said interruption chambers; and wherein no permanent mechanical connection is present between said kinematic chain and said pole assembly.