Comparison of Axial Magnetic Field Characteristics of Four Axial Magnetic Field Vacuum Interrupter Contacts

Magnetic characteristics of axial magnetic field (AMF) of four kinds of vacuum interrupter contacts are studied with 3D finite element method, which included axial magnetic flux density, eddy current in contact plates and phase shift time between AMF and source current. Four AMF vacuum interrupter contacts are studied, which include coil type, cup type, bipolar type and quadrapolar type. The results show that: 1) The strongest AMF at current peak is with coil type contact. It follows by bipolar type, cup type, quadrapolar type with which AMF weakens accordingly. 2) The weakest AMF at current zero is with quadrapolar type contact. It follows by bipolar type, cup type, coil type with which AMF strengthens accordingly. 3) The shortest phase shift time is with bipolar type. It follows by quadrapolar type, coil type, cup type with which phase shift time becomes higher accordingly