The aim of this paper is to describe a software tool dedicated to the design of electromechanical devices. It is based on a serial implementation of an analytical and a numerical procedure. The first one, from datasheet specification give a raisonnable preliminary structure. The second one uses a finite element calculation, associated to a sensitivity analysis and optimization method. For the sensitivity analysis, useful fractional factorial designs are performed to identify the most influential factors and to determine an initial configuration for the optimization procedure.