A cam profile design of a circuit breaker by using multibody dynamics analysis

Abstract

A circuit breaker is widely used to protect electric power system from fault of electric currents or system errors. In this study, a circuit breaker with spring operating mechanism operated by the stored elastic energy of the close spring was addressed. In case of the closing mechanism of this circuit breaker, the torque generated by closing spring rotates the closing shaft. A cam which is located on the closing shaft axis rotates the opening shaft. Several linkages are moved by cam-follower mechanism. In this case, rotating cam is important component for transferring energy generated by closing spring energy. In this paper, multibody dynamic model of a circuit breaker including switch mechanism and cam-follower mechanism was developed using ADMAS. To validate the developed model, the closing velocity of simulation and experiment results was compared. With the developed multibody dynamic model, cam profile optimization was conducted. Cam profile was constructed by spline function including design points. Each point was calculated by radius according to regular interval angle in polar coordinate. Design sensitivity analysis and optimization of cam profile was conducted for decreasing the closing velocity after contacting interrupt.