Electrical machines operating at variable speed generate vibrations, which can be harmful for the machine itself and for its environment. Thus, it is necessary for the manufacturer to take into account noise and vibration at the design stage. There are many tools and methods of analysis, which enable to study coupled phenomena : a classical method is the finite element method (F.E.M) in magneto-dynamics including coupling with circuit and load. However, in the case of strong coupling, these electromagnetic models, vibroacoustic, or thermics, would take a considerable computing time, making structure optimization practically impossible. In order to solve this problem, an analytical multiphysical model is developed for a synchronous machine