VACUUM MONITOR FOR VACUUM INTERRUPTER AND USE OF THE VACUUM MONITOR

摘要

A vacuum monitor for a vacuum interrupter which can detect a poor vacuum pressure from the outside of the interrupter on the basis of the electromagnetic wave signals generated by the electric discharge existing in accordance with a prebreakdown voltage depending upon Pashen's law when vacuum pressure increases within the vacuum interrupter. Since the above-mentioned electric discharge is quite different from so-called partial discharge, even when the fixed and movable contacts are kept closed (i.e. under hot-like condition), it is possible to detect poor vacuum pressure on the basis of the electric discharge existing between the fixed (8) and movable (9) contact rods including two contacts (10, 13) and the main shield (16), as well as when the two contact are kept opened. The vacuum monitor according to the present invention comprises a rod or loop antenna (21) fixedly or movably disposed near a conductive material of or connected to the vacuum interrupter and a detection section (20) including, in particular, a 2 to 20 kHz band-pass filter (24).