Research on the Design of Electric Operating Mechanism for Circuit Breakers

To meet the development requirements of intelligentization and miniaturization of high-voltage circuit breaker actuators and enhance their operational reliability, this paper analyzes the opening and closing motion processes of high-voltage vacuum circuit breaker actuators. The analysis reveals that the energy required to complete the closing operation is higher than that required for the opening operation. Therefore, the energy consumed during the closing process is selected as the target value for the design of the drive motor. The structural parameters of the motor are preliminarily determined based on the motion characteristics of the actuator. To improve the fast response capability and reliability of the drive motor, the stator winding and rotor structure of the motor are optimized. A rotary encoder is employed instead of traditional Hall sensors and angular displacement sensors for electronic commutation and motor speed measurement, thereby enhancing the motor's electromagnetic interference resistance and reliability. The finite element method (FEM) is used to analyze the air-gap magnetic density and magnetic field characteristics of the drive motor under different operating conditions, which further optimizes the structural parameters of the motor. Finally, a prototype of the drive motor is developed and tested in conjunction with the circuit breaker mechanism. The test results demonstrate that the drive motor can reliably meet the requirements for the opening and closing characteristics of the circuit breaker.