Low-Voltage Circuit-Breaker Behavior under Overload Conditions

This article deals with temperature-rise of current path of modern low-voltage circuitbreaker with rotary contact system at overloads and subsequent experimental verification of selected model. The first part describes optimal setting of input conditions of simulation and mainly transient phenomena at contacts causing dynamic change of contact resistances due to change of total contact force, a new challenge to be solved in this contribution. The second part devotes laboratory measurement on prepared sample of the breaker for verification of transient simulation. These simulations are not only important for understanding of rotary system behavior under overloads, but forms an essential part of R & D process due to the speed-up of optimal current path design. In the end, both the financial costs and time effort could be decreased.