Model No.: JTD 12kv 1250A 20KA vacuum interrupter for Solid embedded poles Rated voltage: 12 KV Rated current: 1250A Rated power frequency withstand voltage (1 min): 42 KV Rated lightning impulse withstand voltage: 75 KV Rated short circuit breaking current: 20KA Rated short circuit making current(peak value): 50KA Breaking operations under rated short circuit breaking current: 30 times Rated short time withstand current: 20KA Rated withstand current(peak value): 50KA Rated duration of short circuit: 4 s Mechanical life: 20,000 times Closing force due to bellows and atmosphere: 70±40 N Force required to hold contacts opening at full stroke: 120±50 N Circuit resistance at lowest rated contacts force: =35µO Storage life: 20 years Limiting abrasion of contacts: 3 mm Weight of moveable parts: =0.7kg Mechanical requiements of vacuum circuit breaker Clearance between opening contacts: 7±1 mm Average opening speed: 1.0±0.25 m/s Average closing speed: 0.65±0.15 m/s Rated contacts pressure: 1600±100 N Contacts bouncing duration at closing operation: =2 ms Contacts re-bouncing clearance at opening operation: =2 mm Synchronism of three phases: =1 ms