Note 1 to entry: The hysteresis loss, $Q_{\text{h}}$ , is given by $Q_{\text{h}}=\left(\text{8}/\text{3}\pi \right)f{d}_{\text{f}}\eta J_{\text{ct}}{B}_{\text{m}}$ for a sufficiently high AC magnetic flux density $B_{\text{m}}$ to which $Q_{\text{h}}$ is proportional, where f is the frequency, $d_{\text{f}}$ is the effective filament diameter, $J_{\text{ct}}$ is is the transport critical current density, and $\eta$ is the volume fraction of the superconductor.

Note 2 to entry: This entry was numbered 815-13-59 in IEC 60050-815:2015.