Arc furnace principle
Arc furnaces

As mentioned in the Introduction, the first industrial arc furnaces appeared in the early 20th century.

Initially, the Héroult furnace (figure 1a) had two electrodes, each connected to one terminal of a DC or AC generator. Soon, it was equipped with three electrodes connected to a three-phase network.

At this time, another type of arc furnace was also widely used for steel melting: the Girod furnace (figure 1b). This furnace featured a single top electrode, connected to one terminal of a generator, and several steel bottom electrodes, connected together to the other terminal.

The capacity of these furnaces ranged from...