| 摘要 |
<p>PURPOSE:To prevent a burn-through from occurring by electrically connecting an arc ring composed of a ring conductor with a pressure vessel in a position close to both an insulating spacer and the inner surface of the pressure vessel. CONSTITUTION:An arc ring 5 composed of a ring conductor is provided in a position close to an insulating spacer 3 and the inner surface of a pressure vessel 1, and electrically brought to the ground potential in the same manner as in the case of the pressure vessel 1. When arc 120 moves to the position of the arc ring 5, the tip on the pressure vessel 1 side of the arc 120 moves not to the inner surface of the pressure vessel 1 but to the surface of the arc ring 5 because the arcing ring 5 is arranged in a position closer to a high voltage lead 2 than the inner surface of the pressure vessel 1. Therefore, when the arc 120 is connected in that position, the arc ring 5 is melted and vaporized and a part thereof scatters, but however much the arc ring 5 scatters, such scattering has no effect on the pressure vessel 1 and it is possible to prevent a burn-through from occurring.</p> |
