The electromagnetic repulsion mechanism（ERM） satisfies the high-speed DC circuit breaker’s requirement for the rapidity of the mechanical switch operating mechanism with its high driving speed

but its huge operating force has a strong impact on the transmission system. Aiming at above problems

this paper studies the structural strength of ERM based on ANSYS Workbench. First

a numerical simulation model coupled with magnetic fields

solid mechanics and circuits is implemented. The results show that there are stress oscillations in the pin

connecting rod and armature

among which the chamfering of armature and pin are the weak links of structural strength. Then

based on the simulation model

it is found that as the armature thickness

chamfering radius

circular platform radius

and connecting rod radius rise

the frequency of displacement vibration and stress oscillation of each part increase

while the vibration amplitude and stress peak decrease. Finally

comparative tests are carried out before and after the structural optimization in 40.5 kV mechanical switch. The vibration period and amplitude of the optimized transmission system are smaller

and the action delay is reduced

which verifies the influence of structural parameters on vibration characteristics. The obtained numerical calculation method and rules of structural parameters can be used to guide the design of mechanism.