Abstract: Aiming at the structural limitations of the TGLD-100 automatic transfer switching equipment (ATSE), which lacks effective arc-extinguishing measures and is restricted to AC-33iB utilization category, resulting in severe contact erosion and high welding risks when breaking inductive loads, a novel rotary arc-isolation device was designed. This device is integrated at the bottom of the switch housing and, through mechanical linkage between the moving contact and arc-isolation blades, achieves the functions of evasion during closing and rapid arc interruption during opening。 The article elaborates on the structural design and linkage working principle of the device。 Test results demonstrate that after installing this arc-extinguishing device, the TGLD-100 ATSE successfully met the requirements of the AC-33B utilization category, with fundamental improvement in contact erosion and significant enhancement in electrical lifespan and operational safety, providing an effective technical pathway for performance upgrades of similar products。