AC Loss of MgB2 Superconducting Coils With Alternating Transport Current in Rotating Magnetic Field

In this paper, the authors measured AC losses of an MgB
₂
superconducting (SC) coil being applied to rotating magnetic field and induced alternating current at 20 K. While applying rotating magnetic field to the MgB
₂
SC coil using Halbach array permanent magnet rotor, 0.2-ohm load is connected to the MgB
₂
SC coil to induce transport current in the measurement system. The AC loss of the MgB
₂
SC coil, ohmic loss at the load are measured and estimated by torque meter and current probe, respectively. Also, theoretical estimation via FEM analysis is conducted. The results showed that the measured and calculated AC losses at 80 Hz are7.23 W/cm
³
and 7.17 W/cm
³
, respectively. And measurement and analysis loss results are well agreed among 40–80 Hz.