| 摘要 |
PURPOSE:To prevent an accident of insulation breakdown caused by a foreign metallic substance by a method wherein a container containing a changed member together with an insulating gas is vibrated wholly of partially by a vibrating device, while a voltage impressed on the charged member is raised by stages. CONSTITUTION:A charged member is held, together with an insulating gas, in an earthed container. In the container, an extraneous substance catching means which is nearly free from a field is provided. For instance, such an extraneous catching member as forms a pocket is provided on the lower side of the charged member in the container. A vibration motor or the like is fixed, as a vibrating means, to the container. A portable electric wall-tapping type vibrator, a wooden hammer or the like may be used as well for this purpose. As a means for detecting the extraneous substance, an ultrasonic detector is used, for instance, which is put on the outside the container to detect ultrasonic waves generated when the extraneous substance is vibrated and collides with the inside of the container. In this constitution, an AC or DC voltage is impressed on the container and raised by steps. The extraneous metallic substance being stationary inside the container is suspended and caught by this constitution. Thus, the possibility wherein a foreign substance begins to move under the condition of a long- term operation can be made very small. |
