Detection of Stator-Slot Magnetic Wedge Failures for Induction Motors Without Disassembly

Lee, Kun Wang; Hong, Jongman; Hyun, Doosoo; Lee, Sang Bin; Wiedenbrug, E.; Teska, Mike; Lim, Chaewoong

doi:10.1109/tia.2013.2290869

Cited by 14 publications

(3 citation statements)

References 13 publications

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“…The fault of the magnetic wedge was diagnosed by the inductance. The application of voltage pulse is far less convenient than striking [6] . In 2015, Bossio.…”

Section: Introductionmentioning

confidence: 99%

Research on Non-destructive Intelligence Detection of Tightness of Stator Slot Wedges of Large Hydro-generator

Xie

Zhang

Mao

et al. 2023

Preprint

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In this study, the classification threshold of stator slot wedge tightness is established, and a non-destructive testing technology of stator slot wedge tightness based on acoustics is proposed. Firstly, the classification threshold of slot wedge tightness is determined. Then through the compression test of corrugated plate, the corresponding corrugated plate shape variable is obtained. The mechanical classification threshold is transformed into the deformation threshold of corrugated plate. Secondly, the tightness test platform of stator slot wedge is established and the tightness test is carried out. Then, the percussion signals is preprocessed by endpoint detection method, which greatly reduces the subsequent calculation. Subsequently, the characteristic parameters of the percussion signals are extracted by time-domain and frequency-domain analysis, and the characteristic parameters are screened by F-ratio method and Pearson correlation coefficient method. Finally, the Support Vector Machine(SVM) optimized by cross validation method is used to classify the test sets to realize pattern recognition. The results show that the tightness of stator slot wedge can be accurately detected by using this research. This research realizes the intelligent identification of the tightness of the stator slot wedge of the generator set, and provides an important reference for the tightness detection of the stator slot wedge.

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“…The fault of the magnetic wedge was diagnosed by the inductance. The application of voltage pulse is far less convenient than striking [6] . In 2015, Bossio.…”

Section: Introductionmentioning

confidence: 99%

Research on Non-destructive Intelligence Detection of Tightness of Stator Slot Wedges of Large Hydro-generator

Xie

Zhang

Mao

et al. 2023

Preprint

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“…Stator faults can be classified in three main groups: iron core faults [2], electrical/insulation faults [2] and wedges faults [3]. The most usual stator fault is the inter-turn fault.…”

Section: Introductionmentioning

confidence: 99%

A new space vector approach to detect stator faults in induction motors

Gyftakis

Cardoso

2017

2017 IEEE Workshop on Electrical Machines Design, Control and Diagnosis (WEMDCD)

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“…Stojicic presented in 2011and 2012(Stojicic et al, 2011, 2012 methods to detect missing slot wedges without disassembling. Nevertheless, maintenance is linked with high costs (Lee et al, 2014) and therefore, it is important to know the forces to increase the maintenance interval. It is expected that the damage of the slot wedges is a consequence of its permeability and the direct applied forces, but is not researched yet.…”

Section: Introductionmentioning

confidence: 99%

Damages to magnetic slot wedges in induction machines

Schmülling

Kulig

2015

COMPEL

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Purpose -Magnetic slot wedges are usually installed in open slot high-voltage induction machines. They reduce the no load losses and the magnetization current. Additionally, the leakage inductance increases. However, machines and the slot wedges are getting frequently damaged with a decreasing maintenance interval. The usage of magnetic slot wedges leads to unknown effects. It is possible, that direct magnetic forces or indirect forces, caused by the deformation of the stator or stator teeth during operation, results in the damage of the slots wedges. The purpose of this paper is to fully understand the influence of the magnetic slot wedges and the intrinsic effects. Design/methodology/approach -A finite element model of the affected machine is verified with current and torque values from the data sheet of the affected machine. Three types of forces, which are working on the slot wedges, are considered and compared. Findings -There are direct forces working on the slot wedges. The origin of this forces and a coherence between this forces and the slot number relationship, between stator and rotor slots is shown as well as reasons for the damage to the slot wedges. Originality/value -There are investigations about the influence of the behaviour of an induction machine by magnetic slot wedges. This investigations consider the influence on the network models of such machines. The paper at hand deals with the intrinsic effects caused by the slot wedges and its consequences.(1) the decreasing magnetic air gap leads to a reduction of the no load losses and decreases the magnetization current; and(2) the increasing slot leakage causes decreasing start-up and short-circuit currents.A typical material, used for magnetic wedges in high-voltage induction machines, is MAGNOVAL ® . It has a relative permeability up to m r % 2:9: Table I shows the non-linear magnetic properties of the material, the resistivity κ and its elasticity for mechanical stress analysis.

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Detection of Stator-Slot Magnetic Wedge Failures for Induction Motors Without Disassembly

Cited by 14 publications

References 13 publications

Research on Non-destructive Intelligence Detection of Tightness of Stator Slot Wedges of Large Hydro-generator

Research on Non-destructive Intelligence Detection of Tightness of Stator Slot Wedges of Large Hydro-generator

A new space vector approach to detect stator faults in induction motors

Damages to magnetic slot wedges in induction machines

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