三菱 塑壳断路器；NF1250-SEW 3P A
限流分断能力
Current limiting breaking capacity
断路器发生短路时、触头快速打开产生电弧，相当于在线路中串入1个迅速增加的电弧电阻，从而限制了故障电流的增加。断路器断开时间越少，Ics就越接近Icu，限流效果就越好，也可大大降低短路电流引起的电磁效应、电动效应和热效应对断路器和用电设备的不良影响，延长断路器的使用寿命。
When a circuit breaker is short circuited and the contact is quickly opened, the arc is generated, which is equivalent to 1 rapidly increasing electric arc resistance in the line, which limits the increase of the fault current. The less the break time of the circuit breaker, the closer the Ics is to the Icu, the better the effect of the current limiting effect. It can also greatly reduce the effect of the electromagnetic effect, the electric effect and the thermal effect on the circuit breaker and the electrical equipment, and prolong the service life of the circuit breaker.
短路保护
Short circuit protection
短路保护就是短路瞬时跳闸。要注意在负荷变化后及时调整保护的整定值，防止整定值过小频繁跳闸影响供电质量，或整定值过大使线路和设备得不到有效保护。
Short circuit protection is short-circuit instantaneous tripping. Attention should be paid to adjusting the setting value of the protection in time after the change of the load, so as to prevent the setting value over small frequent trips to influence the quality of the power supply, or the setting value of the ambassador line and equipment can not be effectively protected.