The vacuum circuit breaker with permanent magnetic actuator is a new type of switching equipment with simple structure and high reliability. This study takes the recloser on permanent magnet vacuum column as the research object to put forward new requirements for the permanent magnet mechanism in terms of design

test and standard. The concept of threshold voltage of the power supply capacitor is proposed for the permanent magnet mechanism

and the coil’s discharge current time is defined as "pulse width". It is proved that the combination of "dynamic pulse width" and "static pulse width" can improve the reliability of close control of the permanent magnet actuator. The energy requirements for the permanent magnetic actuator are presented. For the recloser’s operating sequence of"3 times of opening and 4 times of closing"

the graded switching mode of multiple capacitor groups is adopted to perfectly solve the capacity problem of capacitor. Simulation of magnetic field of the permanent magnetic actuator is performed with finite element method to provide a basis for product optimization and reliability design

and a specific assessment method is offered for product testing verification. Simulation and test results verify that the optimization design method can improve reliability of the circuit breakers.