Verfahren zur Bestimmung der Restlebensdauer von Kontakten in Schaltgeräten und zugehörige Anordnung

摘要

In order to establish the residual useful life of earth contacts, it has already been proposed to determine the so-called contact action at the breaker gap as a criterion for replacement in the event of contact erosion and to measure the change in contact action during the switching off stage in order to determine the erosion of the contact tips and convert it into the residual useful life. To that end, with a magnetic drive comprising an armature with magnet coils and an associated yoke, the time taken for the armature to move from the beginning of its movement to the point when the contact starts to open is measured. According to the invention, the measured value of the time signal (tk) of the contact opening is determined on the load side of the monitored switchgear, and the measured value of the time signal (tA) is determined by a de-energized signal emitted at the beginning of the armature movement. Intended in particular for use in three-phase systems, the switching voltage is measured as a change in voltage at an artificial neutral point. The associated arrangement comprises a de-energized signal line (20) disposed between the switchgear (1) and an evaluation device (100, 200, 300).