| 摘要 |
PURPOSE:To prevent a rise in temperature due to local concentration of arc energy on a surface of a main electrode and to improve interruption performance by igniting an arc on a spiral electrode and next by moving the arc immediately to the surface of the main electrode and dispersing it. CONSTITUTION:When a contact surface of a spiral electrode 31 is finally detached, ignition occurs and an arc is magnetically driven toward a peripheral part by electromagnetic force generated by the spiral electrode, so that the arc is made to pass through a ring-shaped high resistance part 29 immediately and to be transmitted to a main electrode 23. When an electrode opening operation of a vacuum interrupter is performed at the near peak time of an arc current, the arc becomes columnar one with high current density, and it becomes very high in its magnetic driving force, and it is transmitted to the main electrode immediately after its ignition. When the arc is once transmitted, an axial magnetic field is generated by a current flowing via a coil part 23b of the main electrode to a short-circuit member 27. Accordingly the arc transmitted to the main electrode becomes a diffusion one by the function of the axial magnetic field to be dispersed uniformly on the surface of the main electrode, so that local heating of the surface of the main electrode can be prevented. |
