Vibroacoustic Models of Air-Core Reactors

Abstract

The purpose of this paper is to provide an overview of the sound power radiation mechanism of air-core reactors and to describe the method that is used to calculate sound power by using the electrical load. Sound power radiation of an air-core reactor is related to the alternating current harmonics, the mechanical tension stiffness and, most importantly, the breathing mode resonance. An analytical model that is based on electrical loads and mechanical properties of the air-core reactor is developed to calculate radial and axial forces caused by the radial and axial magnetic induction fields. This study employs the hemispherical spreading theory, which is a simple and common method that is used to predict sound propagation. Additionally, a numerical model is proposed. In this, the excitation of the acoustic field that surrounds the reactor is introduced by considering the radial and axial displacements of the reactor's windings, as the windings are subjected to the action of the radial and axial electromagnetic forces. Finally, a comparison is presented between analytical and numerical models and it is observed that the models are correlated.

Analysis and Characterization of Noise Generated in Heavy-Haul Railways in Brazil

“…Despite the convenience and advances provided by technological development, environmental degradation is accelerating as other sources of pollution arise. Amongst them, the environmental noise caused by sirens, automotive and domestic alarms, religious temples, horns, transportation systems and other sources, has become a cause of incidents in urban areas (Zannin and Bunn 2014;Fiorentin et al 2013Fiorentin et al , 2016Fiorentin et al , 2017. As a result of urbanization, economic growth and motorized traffic, noise pollution is one of the main sources of complaints in urban areas since it can be detrimental to health, being associated to hearing damage, cardiovascular diseases, irritability, sleep disturbance, headaches, high blood pressure and nervous stress reactions (Stassen et al 2008;Sánchez et al 2017).…”

“…The literature offers solutions for cars, aircraft, electrical systems and others (Fiorentin et al 2013(Fiorentin et al , 2016Oliveira et al 2008). There are, also, some solutions that can be applied to railways, but they are expensive and need to be customized for each railroad.…”

Influence of the multi-component electrical feed of air-core industrial reactors on their sound radiation

“…The results were then compared with a numerical model. This approach was also used in a more recent study [19] with an improvement of the mechanical model and a calculation of Lorentz forces accounting for multi-components. The results obtained for a single layer air-core reactor are successfully compared with tests.…”