Effects of eccentricity on external magnetic field of induction machine

Review of eccentricity fault detection techniques in IMs focusing on DFIG

“…Although magnetic flux monitoring could be considered as a type of electrical monitoring and has been offered in [36][37][38], due to costly and difficult installation of sensors, it has been less respected. On contrary, stator current is easily available and no additional hardware is required.…”

Detection of Static Eccentricity Fault in Saturated Induction Motors by Air-Gap Magnetic Flux Signature Analysis Using Finite Element Method

“…By another eye, several research works affirmed that MCSA has a limited usability to detect faults in induction motor especially in some cases. Usually MCSA is used to detect a high levels of both eccentricity types, it mean when the static and dynamic eccentricity exist together, but it is very difficult to detect such faults if they appear individually [13]- [5], for those authors the fault signatures are presented in stator current spectrum only if the two kinds of eccentricity exist together and it is not easy to distinguish them. In addition, it will be difficult to diagnose the low level static eccentricity with traditional MCSA technique, for them other signals such as noise, bearing vibration and temperature may have to be used in these cases for detecting fault signature [14].…”

“…In addition, it will be difficult to diagnose the low level static eccentricity with traditional MCSA technique, for them other signals such as noise, bearing vibration and temperature may have to be used in these cases for detecting fault signature [14]. Many research works head to use others induction motor quantities to detect SE fault signatures such air gap magnetic flux density [13]- [15], terminal voltages of induction machines at switch-off [5].…”

“…The usability of analysis of external magnetic field to detect faults in induction motor have proved by several papers, the majority of those papers are interested on diagnosis of broken rotor bar [17]- [18]- [14]- [15], stator winding short-circuits [19,20], net voltage asymmetry [21] wound rotor phase disconnection [22], dynamic eccentricity [13]. This paper heads to diagnose low levels of purely SE in induction motor using TSFE method, short description of this technique modeling will be presented in first part of paper.…”

Electrical machine fault analysis and modelling by using electromagnetic approach

“…In the ideal situation when there is no saturation and machine components do not attenuate flux, the stray magnetic field exhibits the similar character of airgap magnetic field. However, in reality, machine stator back yoke is designed as small as possible in order to reduce machine weight and size, so saturation does affect the stray flux [123]. Moreover, the attenuation effect due to machine stator and frame also significantly influence the stray flux.…”