Vacuum-type electrical switching apparatus

摘要

A vacuum-type electrical switching apparatus (10) for high voltage electrical power. A vacuum pressure condition in a vacuum pressure space (21) surrounding electrical contact points (18) is monitored and movement of the contact points between open and closed positions is automatically prevented when the pressure exceeds a predetermined threshold in order to avoid destructive arcing between the points. A sensor (32) provides a vacuum signal (34) responsive to the vacuum pressure condition. A controller (36) automatically inhibits movements of the contact points when the vacuum signal indicates that the vacuum has degraded. A contactor (38) may be placed in series with power supply (28) and a solenoid (24) used to move the contact points, with the contactor being automatically opened by the controller in response to the degraded vacuum condition. An electromechanical opening inhibitor (74) may be energized by the controller to mechanically prevent the contact points from being moved in response to the degraded vacuum condition.