Research of the forces acting on the latch of the vacuum switch vbo-25-20/630 uhl1

The experience gained in the operation of high-voltage vacuum circuit breakers VBO-25-20/ 630UHL1 indicates an incorrect assessment of the mechanical resource of its individual components and elements. Despite the repeated improvement of the design of the main switch drive, applicable both as part of the new «Ermak» series locomotives starting from number 1000 series, and in earlier numbers, the dynamics of malfunctions continues to persist to the present time. One of the most important elements of the main switch is a latch designed to hold the elements of the drive mechanism in the on position, the failure of the latch entails the failure of the entire section of the locomotive. The article considers three latch upgrades previously proposed by the manufacturer, a kinematic scheme of the drive with a vacuum arc-extinguishing chamber of the switch is developed, the parameters of the preload and trip springs in the drive are calculated, the forces operating during operation are determined. On the example of the latest modernization of the latch using the finite element method in the SolidWorks Simulation software package, a strength calculation was carried out, according to the results of which the stresses arising in its design were determined. As a result of the analysis of the finite element model, the forces critical for the structure are determined, a graph of the dependence of the structural strength margin and the maximum stress in the structure on the acting forces is developed. According to the results of the study, the force at which the most favorable value of the safety factor is provided is determined, for which it is proposed to reduce the critical force by changing the parameters of the compression springs and disconnecting the drive of the arc extinguishing chamber. A loading diagram with the drawing dimensions of two modified springs has been developed.