Mathematical modeling of eccentricities in induction machines by the mono-harmonic model

Abstract

The use of mathematical models of faulty induction machine has proved a useful tool for prediction of main effects due to faults. Researches develop mathematical models to use them as base of analysis of practical cases. The induction machine has become one of the most important elements in the industry, which has resulted in increased interest in controlling its operation. Among the usual faults in induction machines mechanical faults represent the 50-60% of the total failures. Those faults have associated in most cases some degree of eccentricity. In this paper a mathematical model of mixed eccentricity effects on induction machine for industrial drives applications is presented. The purpose of the paper is going one step further than previous approach of static and dynamic eccentricities showing that only one model is enough to reproduce successfully all types of eccentricities. Effects of main magneto-motive forces and steady-state performance of the motor supplied by a symmetrical sinusoidal source have been studied making it easy to understand the physical phenomena inside the machine and simplify the mathematical representation of those eccentricities. Based on this approach Matlab/Simulink models can be created for fault diagnosis purposes.