Vacuum Circuit Breaker HVD1-12KV 1250A 25KA VCB with copper parts 210mm phase distance HVD1-12(VS1-12) type indoor AC HV vacuum circuit breaker (hereinafter referred to as circuit breaker) are suitable for 12kV air-insulated indoor switchgears, used as protection and control unit of power equipment of industrial& mining enterprise. Due to the super excellence, it is especially for location where requires the frequent operation of rated working current or multi breaking short circuit current. The circuit breaker adopts the integrated design of operating mechanism and circuit breaker body, servers as not only fixed installation, but also the handcart unit through equipping with a special propelling mechanism. 2. Service conditions 3.1 Environment temperature:-15®C~+40®C; 3.2 Environment humidity: Daily average relative humidity:95%, monthly average relative humidity:90%; Daily average saturated vapor pressure:2.210-3Mpa,monthly average saturated vapor pressure:1.810-3Mpa; 3.3 Altitude: Not exceed 1000m; 3.4 Earthquake intensity: Not exceed°ree; 3.5 Service location: No water, flammable or explosive matter, chemical corrosive gas or drastic vibration. 1.Main specifications and technical parameters Rated voltage: 12 kv Rated lightning impulse withstand voltage(1min): 75 kv Rated short-time power frequency withstand voltage (1min): 42 kv Rated short-circuit breaking current: 25KA Rated current: 1250A Rated peak withstand current: 63KA Rated shorted-time withstand current: 25KA Rated shorted-time making current(peak): 63KA Power frequency withstand voltage of secondary circuit(1min): 2000 v Opening time(rated voltage): 20~50 ms Closing time(rated voltage): 30~70 ms Rated short-circuit current breaking times: 50(40kA 30) times Mechanical life: 30,000 times