| 1. |
- Georgoulas, George, et al.
(author)
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Principal component analysis of the start-up transient and hidden Markov modeling for broken rotor bar fault diagnosis in asynchronous machines
- 2013
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In: Expert systems with applications. - : Elsevier BV. - 0957-4174 .- 1873-6793. ; 40:17, s. 7024-7033
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Journal article (peer-reviewed)abstract
- This article presents a novel computational method for the diagnosis of broken rotor bars in three phase asynchronous machines. The proposed method is based on Principal Component Analysis (PCA) and is applied to the stator’s three phase start-up current. The fault detection is easier in the start-up transient because of the increased current in the rotor circuit, which amplifies the effects of the fault in the stator’s current independently of the motor’s load. In the proposed fault detection methodology, PCA is initially utilized to extract a characteristic component, which reflects the rotor asymmetry caused by the broken bars. This component can be subsequently processed using Hidden Markov Models (HMMs). Two schemes, a multiclass and a one-class approach are proposed. The efficiency of the novel proposed schemes is evaluated by multiple experimental test cases. The results obtained indicate that the suggested approaches based on the combination of PCA and HMM, can be successfully utilized not only for identifying the presence of a broken bar but also for estimating the severity (number of broken bars) of the fault.
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| 2. |
- Islam, M. Jahirul, et al.
(author)
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A study on damper bar and integrated rotor slit of a field winding synchronous machine
- 2021
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In: Proceedings - 2021 IEEE Workshop on Electrical Machines Design, Control and Diagnosis, WEMDCD 2021. ; , s. 16-21
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Conference paper (peer-reviewed)abstract
- This study focuses on the loss reduction and as a consequence efficiency improvement of a synchronous machine by designing a damper bar. The damper bar position is one of the important design parameters to reduce the electromagnetic loss of the salient pole synchronous machine. The total loss of a synchronous machine with a properly designed damper bar and integrated rotor slit can be even lower than the machine without any damper bar or slit. A parametric study has been conducted to study the influence of the damper bar position and dimension of the damper bar integrated rotor slit by rotor bar slot opening height and width. The generator has been modeled and simulated with a re-designed damper bar and integrated rotor slits, without any damper bars or slits, as well as with slits but without any damper bar, thereafter a quantitative comparison has been conducted. The study has been carried out using 2D finite element method on a Multi-MW range field winding synchronous generator. To investigate the accuracy of the simulation results, the influence of the finite element discretization (FED) has been studied by varying the number of nodes and elements.
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| 3. |
- Tsoumas, I. P., et al.
(author)
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Analytical Investigation of the Transient Switch-On Current of Direct-On-Line Induction Motors
- 2019
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In: Proceedings. - : IEEE. ; , s. 3667-3672
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Conference paper (other academic/artistic)abstract
- This work presents an exact analytical equation for the calculation of the switch-on current of induction motors considering the general case of unequal stator and rotor parameters. Based on this analytical solution of the differential equations, the influence of the motor parameters on the amplitude and the duration of the electrical transient is investigated. The exact knowledge of the transient current is necessary for the assessment of its potential impact on transient motor current signature analysis methods for fault diagnosis.
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