Understanding Frequency Response of Induction Motor Winding through Electromagnetic Wave Equations

Abstract

. Frequency response analysis offers an insight about the integrity of machine windings, when employed as a tool for condition monitoring. To ensure that, an electromagnetic wave is injected from one terminal of winding, and the power of the wave at the receiving terminal is measured. The power at the terminals is measured in terms of either voltage or current. This difference in power at the two terminals can be attributed to the medium’s permittivity, permeability and conductivity, through which the signal is being transmitted. This paper offers an explanation for the behavior of the voltage gain frequency response of induction motor winding and propagating medium parameters by employing the fundamental electromagnetic wave equations. Their explanation illustrates how these parameters can affect the response. The correlation established using Maxwell’s equation and these parameters with frequency response analysis is evident while identifying open winding fault and issue with machine core inductance. The results are analyzed and interpreted with the new correlation.