Introduction of the Zero-Sequence Stray Flux as a Reliable Diagnostic Method of Rotor Electrical Faults in Induction Motors

Author(s):  
Konstantinos N. Gyftakis ◽  
P. A. Panagiotou ◽  
E. Palomeno ◽  
Sang Bin Lee
Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2510
Author(s):  
Konrad Górny ◽  
Piotr Kuwałek ◽  
Wojciech Pietrowski

The article proposes a proprietary approach to the diagnosis of induction motors allowing increasing the reliability of electric vehicles. This approach makes it possible to detect damage in the form of an inter-turn short-circuit at an early stage of its occurrence. The authors of the article describe an effective diagnostic method using the extraction of diagnostic signal features using an Enhanced Empirical Wavelet Transform and an algorithm based on the method of Ensemble Bagged Trees. The article describes in detail the methodology of the carried out research, presents the method of extracting features from the diagnostic signal and describes the conclusions resulting from the research. Phase current waveforms obtained from a real object as well as simulation results based on the field-circuit model of an induction motor were used as a diagnostic signal in the research. In order to determine the accuracy of the damage classification, simple metrics such as accuracy, sensitivity, selectivity, precision as well as complex metrics weight F1 and macro F1 were used.


2005 ◽  
Vol 57 (2) ◽  
pp. 181-185 ◽  
Author(s):  
F. Kleiman ◽  
S. Pietrokovsky ◽  
S. Gil ◽  
C. Wisnivesky-Colli

The sensitivity and utility of a standard faecal sedimentation method (FSM) and a modified stool sieving staining method (FSSM), both currently employed for the diagnosis of Fasciola hepatica infection were compared. Faecal samples were obtained from 51 bovines of an endemic area for fasciolosis in Southwestern Argentina. Each sample was placed in a recipient containing 5% formalin. Eight millilitres of the suspension, equivalent to 2g of faeces, were used for each of the two methods tested. The number of eggs found per sample was recorded. The proportion of positive samples obtained by the FSSM (27/51) was significantly higher than that by the FSM (11/51) (P<0.05). The percent of agreement between methods was 41%. Over a total of 27 positive samples detected by the FSSM, the FSM missed 16, yielding 60% false negative samples. The FSSM enhanced 2.5 times the sensitivity of diagnosis. The complexity of the FSM may decrease its sensitivity through missing and loss of eggs during sample processing. These results confirmed that the commonly used FSM underestimates the prevalence and the egg output in cattle and that the FSSM is a more reliable diagnostic method.


Author(s):  
Konstantinos N. Gyftakis ◽  
Dionysios V. Spyropoulos ◽  
Epaminondas Mitronikas

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