| 摘要 |
PURPOSE:To perform a checking of the degree of vacuum without the need for a discharge electrode and an alternate power souce for a high voltage, by a method wherein deterioration in the degree of vacuum is detected by receiving an electromagnetic signal generated by an inner discharge using an antenna and through a band-pass filter of a given band. CONSTITUTION:In case a vacuum circuit breaker is deteriorated in the degree of vacuum, an electromagnetic signal is generated by an inner discharge. Said electromagnetic signal is received by an antenna 16 located in the proximity of the outside of the vacuum circuit breaker, a received signal S1 is inputted to a band-pass filter 24, and only a frequency component of 2-20kHz of the signal is outputted to the filter 24. After said output signal S2 is amplified, it is inputted to a first comparator 26, an integrator 27 and a second comparator 28, while a deviation voltage signal S6 is outputted, and an alarm or a display unit is actuated by means of the output to detect the deterioration in the degree of vacuum. |
