Model No.: TD 12kv 1250A 31.5KA (JUC619A) vacuum interrupter for VCB Main technical parameters Rated voltage: 12 KV Rated current: 1250A Rated power frequency withstand voltage: 48 KV Rated lightning impulse withstand voltage: 85 KV Rated short circuit breaking current: 31.5KA Rated short circuit making current(peak value): 80KA Breaking operations under rated short circuit breaking current: 30 times Rated short time withstand current: 31.5KA Rated withstand current(peak value): 80KA Rated duration of short circuit: 4 s Mechanical life: 10,000 times Closing force due to bellows and atmosphere: 120±50 N Force required to hold contacts opening at full stroke: 190±50 N Circuit resistance at lowest rated contacts force: =20µO Storage life: 20 years Limiting abrasion of contacts: 3 mm Mechanical requiements of vacuum circuit breaker Clearance between opening contacts: 11±1 mm Average opening speed(Contacts closing position~75% contacts opening distance): 1.1±0.2 m/s Average closing speed(30% contacts opening distance~contacts closing position): 0.6±0.2 m/s Rated contacts pressure: 3150±200 N Contacts bouncing duration at closing operation: =2 ms Contacts re-bouncing clearance at opening operation: =2 mm Synchronism of three phases: =1 ms * It Needs additional insultating protection.