Electric arc furnace general introduction

Electric arc furnace is actually called submerged arc furnace. It can be divided into DC electric arc furnaces and AC electric arc furnaces according to the current form.

1. AC electric arc furnace

The structure of the AC furnace is relatively simple. The three-phase AC power is connected to the three electrodes. And there is no complicated rectifier circuit, so the cost is relatively low. However, the arc is unstable. Moreover, the power factor of the AC furnace is low, 0.85 on average, which means that 15% of the electric energy is wasted, and a reactive power compensation device must be added to increase it to 0.9. At the same time, each set of exchange furnaces are calculated and designed in strict accordance with the conditions of the materials. So you cannot change the properties of the raw materials arbitrarily. The arc length of the AC furnace cannot be changed arbitrarily.

2. DC electric arc furnace

DC electric arc furnace needs a rectifier circuit to convert alternating current into direct current. In the case of DC, the arc can be maintained in a stable state. The power factor of the direct current furnace can generally reach above 0.9. According to the number of electrodes, DC furnaces are divided into single-electrode furnaces and double-electrode furnaces. There is only one graphite electrode above the single-electrode furnace, which is the negative electrode. The positive electrode is at the bottom of the furnace, which is called the bottom electrode. Both the positive and negative graphite electrodes of the double-electrode furnace are above the furnace. Most DC furnaces on the market are single-electrode furnaces. But the single electrode furnace has a serious problem that the bottom electrode is easily melted at a high temperature.