Fault indicator having electrostatically-actuated indicator flag

摘要

A fault indicator for indicating the occurrence of a fault current in a monitored conductor includes an electrostatically-actuated indicator assembly. During normal operation a lightweight indicator flag rotatably mounted in and viewable from the exterior of the indicator housing is held in a reset-indicating position by electrostatic force resulting from an electric field existing between the flag and adjacent electrodes. Upon occurrence of a fault current in the monitored conductor the electric field is removed and the indicator flag, under the influence of a permanent magnet, is caused to rotate to a fault-indicating position. By avoiding the use of magnetic actuator windings and associated pole pieces the indicator assembly is easier and more economical to construct.