A Novel Approach for Early Detection of Inter-turn Faults in Induction Motors during Start-up

Early inter-turn faults (ITFs) are one of the most challenging and important faults to detect due to their rapid evolution into a catastrophic stator failure, which, in turn, is one of the main reasons for motor failures in medium and high-voltage induction motors (IMs). Despite all this, there is an under-representation of this topic in the technical literature. This under-representation is even more significant when it comes to transient analysis. Yet, today’s computer capabilities open up the possibility of filling this gap through the combined use of finite element software (as safe test-benches to study the fault) and powerful time-frequency tools. This paper aims to contribute to this gap by thoroughly investigating the diagnosis of early-stage ITFs during IM start-up. The first part of the work conducts a deep finite element analysis of three motors of different characteristics that leads to discovering and fully characterizing a family of ITFs-related harmonics not described before in previous literature. Finally, their existence is proven in a 0.75 kW IM through a novel methodology that emulates the electromagnetic effects of an ITF but without endangering the stator’s windings.