Bistable magnetic actuator for a medium voltage circuit breaker

A medium voltage circuit breaker comprising:

• at least one vacuum interrupter, wherein each interrupter includes:
• moving electrical contacts for electrical power interruption, operating via a common jackshaft for mechanically coupling the moving electrical contacts with a bistable magnetic actuator,
• wherein the bistable actuator includes:
• at least one electrical coil for switching a ferromagnetic armature between a first limit position and a second limit position effected by an electromagnetic field;
• at least one permanent magnet for holding the armature in one of the two limit positions corresponding to an open and a closed electrical switching position respectively of the mechanically connected circuit breaker,
• wherein the armature includes an upper plunger resting on a ferromagnetic core element of the one electrical coil for static holding the armature in the first limit position, which is attached to a plunger rod extending through the ferromagnetic core element and through the permanent magnet for mechanically coupling the actuator to the circuit breaker arrangement, and
• wherein the armature includes a lower plunger releasably attached on the opposite side of the plunger rod in an axial distance from the core element via fixing means for fastening or releasing the lower plunger on the plunger rod and movable on the core element to shift the armature to the second limit position by reducing the magnetic flux in the upper plunger.

A vacuum interrupter, comprising:

• moving electrical contacts for electrical power interruption, operating via a common jackshaft for mechanically coupling the moving electrical contacts with a bistable magnetic actuator,
• wherein the bistable actuator includes:
• at least one electrical coil for switching a ferromagnetic armature between a first limit position and a second limit position effected by an electromagnetic field;
• at least one permanent magnet for holding the armature in one of the two limit positions corresponding to an open and a closed electrical switching position respectively of the mechanically connected circuit breaker,
• wherein the armature includes an upper plunger resting on a ferromagnetic core element of the one electrical coil for static holding the armature in the first limit position, which is attached to a plunger rod extending through the ferromagnetic core element and through the permanent magnet for mechanically coupling the actuator to the circuit breaker arrangement, and
• wherein the armature includes a lower plunger releasably attached via fixing means for fastening or releasing the lower plunger on the plunger rod on the opposite side of the plunger rod in an axial distance from the core element and movable on the core element to shift the armature to the second limit position by reducing the magnetic flux in the upper plunger.