VACUUM CIRCUIT BREAKER

PURPOSE:To simplify the constitution of an operating mechanism and make maintainance-inspection easier with improvement in reliability by providing a flywheeling cam having a circular protrusion, a lever having a recessed part engaging with the protrusion, and a microswitch. CONSTITUTION:A flywheeling cam 19 engaging with a roller 5 is attached rotatably in an operating mechanism frame 1, the cam 19 being drived with a coaxially fixed large gear 20 working on one another by teeth with a small gear 21 fixed to a rotating axis of a motor, and a cylindrical protrusion 22a fixed coaxially having a semicircular notched part 22a engages with a lever 23. And, the protrusion 22 and a recessed part 23b provided in the lever 23 fitting therewith, enable the lever to be mechanically holded while motor rotating, so that only one microswitch makes the mechanism configuration more simple as well as easy maintainance-inspection. And, adjusting circumferential shapes of both the arcuate notched part 22a provided on the protrusion 22 mounted integrally with the cam 19 and the lever 23 engaging with it, reliable stop at the indicated position can be performed, so that reliability of function can be improved in mechanism.