Theoretical and numerical stress analysis in the cam of a medium voltage switchgear vacuum circuit breaker supported by image processing of deformation

Vacuum circuit breakers (VCBs) are widely used in the switchgear industry. Over the past decades, leading companies have conducted extensive research and development to optimize the mechanical mechanisms and understand the kinematics and dynamics behavior of VCBs. The mechanical life of these devices is crucial for safety and reliability. This paper investigates an essential component of the VCB mechanism by evaluating the stress in the cam using theoretical and numerical methods. Furthermore, the calculations are supported by examining a deformed cam in a VCB after 2500 cycles. To this end, contact stress equations for the cylindrical part of the cam and its follower were developed. The ABAQUS finite element software was employed with specified contact properties. Additionally, an image of a cam in a VCB after 2500 cycles was processed and compared to other methods. The results demonstrate that the cam exhibited alternating stress values at different local locations at the end of its profile. However, in general, the Von Mises stress increased as the location on the cam progressed from 0° to 240°.