| 摘要 |
<p>PURPOSE:To enable the screening of a physically and mechanically damaged zinc oxide element by measuring a sound generated from the element by a vibration sensor and detecting the generated sound. CONSTITUTION:Currents (i) corresponding at the specified level of screening are applied from the high-voltage terminal of a zinc oxide element 2 through a current transformer 1 for a certain time from a power supply 8, and electricity is conducted from an electrode 3 to ground. When physical and mechanical breakdown such as a crack is generated in the zinc oxide element 2 at that time, a sound is generated with the breakdown. The sound is detected by a vibration sensor 4 placed on the electrode 3, and an output from the vibration sensor 4 is amplified by an amplifier 5, and recorded by a recorder 6. On the other hand, outputs from the current transformer 1 and a transformer 7 measuring the voltage of the high-voltage terminal of the zinc oxide element 2 are input to the recorder 6, and the recording of the recorder 6 is investigated, thus determining a point in time of the generation of the crack in the zinc oxide element.</p> |
