| 摘要 |
<p>PURPOSE:To reduce an effect at the time of the breakdown of a varistor element on a housing for an arrestor by forming insulation level difference to insulating layers shaped inside and outside the columnar varistor element with a hollow section and creeping-discharging the insulating layer at a low insulation level in the marginal discharge resistance or less of a varistor sintered body. CONSTITUTION:When lightning surge voltage is applied between electrodes 7 for varistor elements, surge currents with these voltage are flowed through the varistor elements, and voltage among the varistor elements is inhibited. The insulation levels of internal insulating layers 6 in internal hollow sections in the varistor elements are lowered until surge currents are increased and reach the marginal discharge resistance of the varistor sintered bodies, thus generating creeping discharge on the surfaces. Consequently, a breakdown mode to surge currents of the varistor elements is generated as creeping discharge at all times, and the creeping discharge is generated positively in the internal hollow sections. Accordingly, a mechanical effect on a housing for an arrestor can be relaxed.</p> |
