Influence of Saturation Level on the Effect of Broken Bars in Induction Motors Using Fundamental Electromagnetic Laws and Finite Element Simulations

This study is dedicated to faulty induction motors. These motors are often used in industrial applications and the monitoring of their condition becomes important for production maximization. This paper gives precise understanding of the effect of the broken bar on the stator currents, a quantity more and more used for fault detection and quantification. This study uses 2-D finite element (FE) models for detailed field analysis and considers different saturation levels (voltage levels). Fundamental electromagnetic laws are used to interpret FE results. It is shown that the presence of local saturation tends to lower the effect of a broken bar on the stator currents. This effect increases with the voltage level and must be taken into consideration for precise quantification of the fault. Furthermore, on a local point of view, the presence of a broken bar leads to highly saturated regions in the neighborhood of the broken bar that will influence the progression of the fault.