This paper describes a methodology for determining the interdependencies between individual characteristics of synchronous machines using numerical experiments and for replacing the interdependencies with the analytical expression in a polynomial format. This approach facilitates further investigations, since it allows to replace real experiments. The proposed methodology is easy to implement with computer technologies. The method is based on the mathematical modelling of magnetic field using partial differential equations of derivatives in relation to the magnetic vector potential, realized by the method of finite element. This method, which is described here and proven theoretically, offers how to obtain the vectoral magnetic potential as a spatial coordinate and a time function as well as to determine its characteristics by mathematical modelling of stationary magnetic field. Offered, in theory proved, and described method proposes how from a stationary magnetic field’s mathematical modelling the vector magnetic potential as a spatial coordinates and as a time function, necessary characteristics are obtained