Dynamic analysis and design of the vacuum circuit breaker with a spring-actuated linkage and cam mechanism

Abstract

The closing and opening characteristics of electric contacts in a vacuum circuit breaker depend on the high-speed operating mechanism with a spring-actuated cam and linkage system. The systematic studies on the dynamic problems of the operating mechanism and the design method of a spring-actuated cam and linkage have not been very sufficient. In this paper, therefore, the dynamic model for analysis and design of a high-speed circuit breaker mechanism for the rapid closing and opening operations has been developed. Here, we demonstrated that multibody dynamics programs can be an effective method to model a vacuum circuit breaker mechanism, which has complex kinematics, friction, spring vibration in the transverse direction, impact, and different configurations for the closing and opening operations. The characteristics of the friction at the camshaft were analyzed using the nonlinear pendulum experiment and the optimization technique. The friction analysis exhibited that the friction of the pendulum depends on stick-slip, Stribeck effect and viscous damping. Based on the observation of closing spring motion, the analysis of the spring model revealed that the spring is more than a simple forcing element and its dynamic model is modeled as four-degree-of-freedom lumped masses connected with equivalent springs. The appropriateness of the hybrid friction model and the lumped spring model were verified by its application to a vacuum circuit breaker mechanism of the cam-follower type. As applications of the derived dynamic model, we have applied the proposed hybrid friction model and lumped spring model to the dynamic analysis of a vacuum circuit breaker with different interrupting capacity. Comparing the simulation results with experimental responses, the appropriateness of the proposed modeling procedures was enhanced more and more. From energy flow analysis for the opening operation, the concept design of the new operating mechanism with less energy efficiency was...