It indicates that the rotary-arc gap switch employing a sharp knife-edge electrode as a third trigger electrode can distinctly reduce the electrode erosion and prolong the lifetime of the switch.

And has a CNC vertical lathe, boring machine large landing, automatic gap submerged arc welding, electro-optical tracking cutting machine and a variety of measurement test equipment.

Such horizontal magnetic field will make the arc move out of the electrode gap, and reduce the interrupting ability of the vacuum interrupters.