Efect of Linkage Flexibility on Dynamics of High-Capacity Outdoor Circuit Breakers

This paper has attempted to survey some of the significant manifestations of linkage flexibility on large oil circuit breakers. Due to the inherent mechanical complexity and nonlinearity which are characteristic of these devices a rigorous mathematical study can become extremely formidable. The major omissions which have been made in this study include the nonlinear effects of the linkage kinematics and, probably more important, the internal dissipation of strain energy because of friction and backlash in the linkage. Fortunately, both these effects are least significant in the region of greatest interest, namely the behavior of the system near the closed position. The simplified analyses which have been described are capable of demonstrating many of the influences which are of interest and, properly employed, yield results of the proper orders of magnitude. As has been shown, flexibility of the linkage of the large circuit breaker has an important influence on at least the following aspects of circuit-breaker mechanical behavior: 1. The time lag between trip impulse and motion to contact-part position in normal trip operation. 2. The time elapsed between contacttouch and contact-part position in tripfree operation.