In this paper a novel axial magnetic contact for vacuum interrupters is designed

which has the desired magnetic field distribution and the excellent breaking property.The asymmetric contact structure is composed of a static contact

which has two coils in series

and a moving contact without any coil.Therefore

the structure of the moving contact will be simplified

its mechanical strength be enhanced

and its weight be reduced

which is helpful to raise the breaking speed of the vacuum interrupter.Using finite element method

the 3-D electrode model is built and the simulation for the axial magnetic field has been carried out.With the amplitudes of the breaking current at peak and zero

it would be calculated the axial magnetic Field distribution at static contact surface

at moving surface

and at the middle plane between the static and moving contact

respectively.The phase delay time of the axial magnetic field is considered as well.The simulation results provide that this asymmetric structure of the axial magnetic field contact can generate strong and uniform axial magnetic field.The amplitude of the residual magnetic field is small and its phase delay time after the current zero is short.Moreover

the resistance in the conductive loop is small.