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.