3-dimensional magnetic field calculation for an arrangement of SC coils with an outer magnetic core

The magnetic field calculation program described allows fast and detailed calculation of 3-D field distributions in coil arrangements with magnetic cores. To determine the maximum current density for an arrangement of superconductor (SC) coils at a given temperature, the magnetic field distribution within the coils has to be known exactly. The magnetic field distribution to the coils is determined by replacing the coils by current filaments and by the use of the Biot-Savart equation. Better results are obtained when the Biot-Savart equation is integrated over finite coil elements of a pregiven form, for which analytic integration is possible. The outer iron core is represented by magnetic surface polarities. The authors describe the combined use of these methods for the total field computation and compare computed and measured results. The program proved useful for the determination of the field maximum and the force distribution in the field winding of an SC synchronous generator