Influence of imperfect joints and geometrical tolerances on a circuit breaker dynamics

The aim of this paper is to understand the influence of clearances in the kinematic joints, dimensional and geometrical tolerances associated with the parts, on the performance of a circuit breaker mechanism in the trip operation. Operating mechanism and trip unit are the essential components of a miniature circuit breaker. The operating and trip mechanisms are made of ten parts with revolute and cylindrical joints with clearance, and five unilateral contacts with friction. This mechanism is based on quick-make and quick-break principle. The Moreau-Jean nonsmooth contact dynamics (NSCD) numerical method is used to perform the simulations. The numerical results are validated by careful comparisons with experimental data.