A reactance ballast device, in particular for an arc furnace, has an induction coil and a free-standing load stepping switch, with the load stepping switch being designed to adjust the reactance of the induction coil while on load. However, the operational efficiency of these pilot valves can suffer from imperfections due to manufacturing defects, wear, and the like, thereby impairing the control system’s overall performance. The notifying portion prompts an exchange of the web when the detecting portion detects the displacement of the contact portion when the number of times is not less than the predetermined number.