Simulation and analysis of inter-turn short-circuit fault in a 3-phase induction machine using an internal equivalent circuit model

Abstract

This work develops a circuit-based simulation framework dedicated to the study of stator inter-turn short-circuit (ITSC) defects in three-phase induction machines. The formulation relies on an internal equivalent circuit (IEC) description in which every stator coil and rotor bar is characterized individually through its own electrical quantities. This strategy preserves the physical structure of the machine and enables localized and parameterized fault injection (shorted-turn ratio β and fault resistance Rf) by modifying only localized resistance and inductance values. The model is implemented using MATLAB/Simulink software and validated through experimental measurements obtained from a dedicated test bench under both healthy and faulty conditions. Frequency analysis based on FFT is used to identify distinctive fault signatures. The results show a characteristic fault harmonic at 98 Hz (β = 5%, R f = 0.5 Ω), confirming the theoretical predictions. The proposed model demonstrates its suitability as a computationally light yet physically meaningful simulation tool for fault analysis and diagnostic algorithm development in 3-phase induction machines under ITSC fault conditions.