Electric arc furnace environment and conditions

 Electric arc furnaces used for smelting generally have three characteristic working stages:

• At the beginning of the melting stage, the solid charge is melted and the energy demand is the largest

  
  

• Initial refining and heating stage

  
  

• During the refining period, the input energy at this stage only needs to balance the thermal damage

The smelting cycle of an ordinary AC electric arc furnace is about 3~8h, depending on the parameters of the power supply circuit, the capacity of the electric furnace, and the smelting process. The melting period is about 0.5~2h, it is a three-phase asymmetrical impact load, the current is extremely unstable, and the power consumption is large, accounting for about 60% to 70% of the total power consumption. During the refining period of oxidation and reduction, voltage fluctuations and power consumption are significantly reduced.

The working characteristics of electric arc furnace during scrap smelting are:

The arc frequently cuts off and re-ignites when melting begins

•  Arc fluctuations occur during the full melting period and lead to sharp current changes

  
  

•  Material collapse caused short circuit

The power factor of ordinary electric arc furnace loop operating point ranges from 0.8 to 0.85; for high-power electric arc furnaces, it is between 0.7 to 0.8. The lower power factor will inevitably lead to the low power efficiency.