Application of a dynamic model based on a network of magnetically coupled reluctances to rotor fault diagnosis in induction motors

The growing application of asynchronous motors in industrial processes that require high security and reliability levels has led to the development of multiple methods for early fault detection. The design and verification of these methods imply the use of complex mathematical models that allow the study of the influence produced by the machine operating conditions over the diagnosis procedure. The present paper describes a model for asynchronous motors based on a network of magnetically coupled reluctances. The aim of this model is its application to the study of the typical failures of this type of machine i. e. rotor asymmetries, air gap eccentricity, operation with an open phase etc. The dynamic properties of the model allow the simulation of the spatial evolution of all the motor variables, without neglecting complex phenomena such as magnetic saturation. Time domain analysis of air gap torque, as well as the calculation of current harmonic components is also possible. This initial study is aimed to check the accuracy and computation economy of the model. To do this, the model win be used to analyse a new diagnosis method for rotor fault detection. Simulations of healthy and faulty motors will be presented and the evolution of the machines main electrical and mechanical variables will be obtained.