TD 12kv 1250A 31.5KA (JUC618) vacuum interrupter for VCB
Main technical parameters
Rated voltage: 12 KV
Rated current: 1250A
Rated power frequency withstand voltage: 42 KV
Rated lightning impulse withstand voltage: 75 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: 4S
Mechanical life: 20,000 times
Closing force due to bellows and atmosphere: 120±50N
Force required to hold contacts opening at full stroke: 190±50N
Circuit resistance at lowest rated contacts force: �20μΩ
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: â?¤2 ms
Contacts re-bouncing clearance at opening operation: â?¤2 mm
Synchronism of three phases: â?¤1 ms