Current filament models have been widely -the system equations depend on the values of the used for the electromagnetic analysis of induction electrical parameters of the network, and launchers and elecbOmagnetic devices. In this consequently on the precision to which the paper two functions of the eigenvalues of the fila-parameters are calculated; mat parameter ma& were determined in Order -the number of volume elements in which the evaluate: -the errors on the system solution, induced by approximate calculations of the matrix parameters: -the influence on the solution, of a variation of the fllament number of the discretization.These functions allow an estimate of the solution convergence, and accuracy, avoiding the numerical or analytical integration of the differential equation set of the system. The launcher has been modeled by means of a coordinate system coherent with the moving armature, with the hypotheses of piecewise constant velocity of the armature. in order to have not time dependent elements in the system matrix.