| 摘要 |
PURPOSE:To aim at lowering the cut current by selecting a specific tungsten carbide particle in a contact material made of the eutectic crystal of copper silver, cobalt and tungsten carbide. CONSTITUTION:The smaller a tungsten carbide particle, an arc-resistant material in contact material, is, the smaller its cut value is, but from the economical point of view, the easiness in making and the effect are correlative so that it is important to select an effective particle size distribton. The tungsten carbide made of more than 80 percent of the particle with its diameter being below 0.8mum and less than 10 percent of the particle with its diameter being over 1mum is selected. The cut current value can be thus considerably lowered. |
