The purpose of this paper is to present the original study of an industrial reactors with different air-gap materials in order to reduce vibration and noise of reactors. Acoustic comfort is an increasingly important factor at the design stage of industrial reactors associated to converters. In addition, power converters in railway domain are more and more compact and powerful. Design/methodology/approach – Experiments, simulations and test devices are used to determine the main physical phenomena that generate the undesirable audible noise. Electric and vibratory measurements (modal and operational analysis) are compared with the numerical calculations. PWM and sinusoidal supply are taken into account and different prototypes with different materials in the air-gap are built. Findings – This study analyzes and details the origin of the electromagnetic noise due to the vertical mode, in order to reduce vibration and noise of reactors. A detailed analysis by finite element simulation and experimental measurements of free-free mode or forced mode under electrical excitation was conducted to interpret the vibrations of the structure. In addition, in order to observe trends and the impact of magnetostriction effect, we propose a simplified model.