Fire accident can arise from low-voltagearc fault, and so it is necessary to detect arc fault.
低压故障 电弧有引发火灾的危险，所以检测故障 电弧是必要的。
2
But the argon plasma arcvoltage, low enthalpy is not high, cutting ability is limited, and cut the air than the thickness of the cut about 25% lower.
但氩气等离子弧的电压较低，焓值不高，切割能力有限，与空气切割相比其切割的厚度大约会降低25%。
3
The characteristics of arc furnace are lowvoltage, big current and nonlinear load. Much negative sequence current is produced during running. As a result, the power net is unstable.