Intermediate-frequency External Axial Magnetic Field for Current Interruption Experiment

In this paper, an external axial magnetic field (AMF) applied in intermediate-frequency current interruption experiment is designed. In the excitation system, an intermediate-frequency current transformer is designed to induct current in main circuit and the secondary current is used to excite the Helmholtz coil, thus the AMF, which is synchronous with primary current, is generated in axes center of the Helmholtz coil, by which the magnetic field generated by contact coil can be simulated. The experiment is implemented to test the excitation system. The magnetic induction intensity is calculated according to the supposed mathematic model of circuit and experimental data in the AC experiment. The calculation results of B/I turn out to be consistent with the theoretical value, which proves the effectiveness of this excitation system.