Abstract: This research is devoted to the study of the two layer winding permeances with round conductors placed in the stator by Asymmetrical Placement Method (APM) without double flexion. An application criterion of these winding types is proposed. Theoretical and experimental analyses are centred on the performances of the proposed new method of two layer winding placement-Symmetrical Placement Method (SPM) starting from the polynomial model based on the multifactorial experiment in order to replace the generally utilised methods: "lifted" and asymmetrical methods. The obtained results made it possible to highlight a lifespan variation law according to the temperature in an interval of humidity values.