AC Losses Analysis and Experiments of Superconducting Electromagnetic Iron Separator

A 3 T central field Superconducting Electromagnetic Iron Separator (SEIS), which was designed to separate dangerous ferromagnetic materials, such as detonators, from coal, has been successfully developed at Institute of High Energy Physics (IHEP). The SEIS magnet is mainly composed of a NbTi solenoid coil, a pair of binary current leads (CL) and a re-condensation cryostat with two GM cryocoolers (31 W/40 K, 1 W/4.2 K). Powered with a 250 A/50 V power supply, the magnet has 15 minutes of charging time and 20 minutes of discharging time. The AC losses, mainly consist of hysteretic loss and coupling loss, was calculated with a two-dimensional ANSYS FEA model. The effect of AC losses on the temperature distribution within the cold mass and its induced cryostat pressure rise were analysed during charging process. With regard to the cryostat pressure rise, the analysis results were quite close to the experimental results.