| 摘要 |
<p>PURPOSE:To improve the voltage withstandability without enlarging the profile by mounting insulation disc shields having crescent cross-section on the facing surfaces between contactors thereby relieving the inter-pole field. CONSTITUTION:Insulation shields 12 having disc type side section and crescent cross-section injection molded with epoxy resin together with contactors 11F, 11B with a hole 12d being made in the center are mounted at the facing sides of the contactors 11F, 11B. The insulation shield 12 has flat central section, when viewed from the side face, and a large curvature is provided upto the outer edge having small curvature. Since the voltage is born by the insulation shield 12 as well as the contactors 11F, 11B, the stress E1 in the facing surfaces of the insulation shields 11F, 11B is reduced when compared with conventional art. During inter-pole spark, electrons are discharged from section E3 to section E1, but because of voltage bearing and large curvature at the section E1 the voltage withstandability is increased resulting in reduction of the size.</p> |
