Analysis of axial magnetic field of an iron style bipolar axial magnetic field vacuum interrupter

Iron style bipolar axial magnetic field vacuum interrupter is a novel vacuum interrupter and it is the first one that is developed in China. Its axial magnetic field in the gap and eddy current in the iron core are analyzed. It is shown from the static axial magnetic field analysis that its axial magnetic flux density is very high and its distribution is homogeneous on the iron area. The axial magnetic flux density will increase significantly when electrode diameter increases or gap decreases. When the arm width increases the flux density will decrease almost linearly. It is shown that eddy current is related to electrode structure parameters and iron material property. When contact diameter decreases or arm width increases, eddy current will decrease. When gap increases eddy current will decrease slightly. Eddy current will increase nonlinearly with the increase of magnetic permeability and generally does so with the increase of conductivity. It is also shown that a laminated iron core is a good way to reduce eddy current. Since the iron core has an important influence on the AMF, an improved iron core design is obtained