| 摘要 |
PURPOSE:To improve a large-current cutout performance as well as a small- current cutout performance by fitting a contact to the tips of ring-shaped contact point electrodes respectively at the sides of a fixed electrode and a movable electrode, and constituting both of said ring shaped contact point electrodes with a material having high voltage resisting characteristics and both of said contacts with a material having low surge characteristics. CONSTITUTION:At the time of cutting our a large amount of current, an arc is diffused to other than contacts 121 and 122. As a result, an arc is ignited on ring-shaped contact point electrodes 112 and 114. The arc ignited on the ring-shaped contact point electrodes 112 and 114 made of a material having high-voltage resisting characteristics turns and shifts therealong at a high speed, due to a radial magnetic field. Consequently, the abrasion and damage of the contact point electrodes 112 and 114 are alleviated and it is possible to cut out a large amount of current. On the other hand, in the case of a small amount of current, the radial magnetic field is small and the arc stays on the contacts 121 and 122. And the current is cut out with the low stage characteristics of the contact comprising a low surge material. |
