Electromagnetic analysis in devices with sliding contacts

In this paper an integral formulation for the analysis of systems with moving conductors has been extended to take into account the presence of sliding contacts. The proposed formulation results in the equilibrium equations of an equivalent electric network whose elements vary with the position of the conductors. The phenomena occurring at the interface between conductors involved in sliding contacts have been investigated by the introduction of an auxiliary electric network. The formulation has been applied to the electromechanical analysis of a rail launcher. Because of the short operating times involved in these devices the thermal behaviour has been taken into account by a simple adiabatic model; the temperature distribution obtained is used to update the resistivity of the elements of the network produced by the integral formulation. The results of the simulations show the capability of the model to take into account the characteristic phenomena of these devices.