Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662532
S.J. Hoffe, A. Meyer, W. Cronje
Shaft voltages and currents are an unavoidable characteristic of rotating machines. Recently there has been renewed interest in the diagnostic possibilities of these signals. This paper presents a technique to determine the mechanical shaft position using a capture of the shaft voltage and a mechanically aligned pre-recorded reference. The tests were carried out on a 400 V salient 4-pole generator with rotating exciter. Gold-bristle brushes were used which provided excellent signal clarity. A PC based acquisition system was used which facilitated averaging to further reduce noise as well as the capture of absolute position using a rotary encoder. The technique successfully determined the shaft position using a test signal which was considerably distorted. This technique could prove useful in the location of faults within a machine, and investigation is continuing.
{"title":"Determination of shaft position from shaft voltage on a synchronous generator","authors":"S.J. Hoffe, A. Meyer, W. Cronje","doi":"10.1109/DEMPED.2005.4662532","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662532","url":null,"abstract":"Shaft voltages and currents are an unavoidable characteristic of rotating machines. Recently there has been renewed interest in the diagnostic possibilities of these signals. This paper presents a technique to determine the mechanical shaft position using a capture of the shaft voltage and a mechanically aligned pre-recorded reference. The tests were carried out on a 400 V salient 4-pole generator with rotating exciter. Gold-bristle brushes were used which provided excellent signal clarity. A PC based acquisition system was used which facilitated averaging to further reduce noise as well as the capture of absolute position using a rotary encoder. The technique successfully determined the shaft position using a test signal which was considerably distorted. This technique could prove useful in the location of faults within a machine, and investigation is continuing.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124284823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662522
E. Blanco, O. Ondel, A. Llor
This paper deals with pattern recognition (PR) method associated with a tracking and a prediction of evolution for various operating modes of a process. The aim is to improve diagnosis of a process by enhancing its knowledge database. Indeed, PR needs an initial database named training set. It is composed of different operating modes and obtained during the first step of PR. It is commonly named training phase. It is a laborious step and moreover the whole of operating modes is never available (generally poor experimental feedback). Thatpsilas why, using knowledge in training set, it is interesting to predict evolution of operating modes in unknown fields of representation space. PR steps are first presented and followed by a polynomial approach of tracking evolution. Next, a Kalman algorithm is used to predict evolution and finally two different asynchronous machines (5.5 kW and 18.5 kW) are used to illustrate our purpose.
{"title":"Using linear interpolation and Kalman prediction in Pattern Recognition: Application to an induction machine","authors":"E. Blanco, O. Ondel, A. Llor","doi":"10.1109/DEMPED.2005.4662522","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662522","url":null,"abstract":"This paper deals with pattern recognition (PR) method associated with a tracking and a prediction of evolution for various operating modes of a process. The aim is to improve diagnosis of a process by enhancing its knowledge database. Indeed, PR needs an initial database named training set. It is composed of different operating modes and obtained during the first step of PR. It is commonly named training phase. It is a laborious step and moreover the whole of operating modes is never available (generally poor experimental feedback). Thatpsilas why, using knowledge in training set, it is interesting to predict evolution of operating modes in unknown fields of representation space. PR steps are first presented and followed by a polynomial approach of tracking evolution. Next, a Kalman algorithm is used to predict evolution and finally two different asynchronous machines (5.5 kW and 18.5 kW) are used to illustrate our purpose.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128130252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662503
A. Boscolo, G. Rabach, M. Visintin
A synthetic description of the phenomena induced by PWM inverter drive systems are reported and the parameters related to motor reliability are evaluated. The winding quality of brand new motors is addressed, specifically the integrity of the turn or the conductor insulation is checked by applying surge voltage stresses. Finally Partial Discharge (PD) measurements are carried out on an aged 800 kW motor: the outcomes are reported and discussed.
{"title":"Evaluation of LV insulating systems in inverter fed electric motors by means of partial discharges","authors":"A. Boscolo, G. Rabach, M. Visintin","doi":"10.1109/DEMPED.2005.4662503","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662503","url":null,"abstract":"A synthetic description of the phenomena induced by PWM inverter drive systems are reported and the parameters related to motor reliability are evaluated. The winding quality of brand new motors is addressed, specifically the integrity of the turn or the conductor insulation is checked by applying surge voltage stresses. Finally Partial Discharge (PD) measurements are carried out on an aged 800 kW motor: the outcomes are reported and discussed.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132235622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662498
I. Soran, I. Sztojanov
The power measurement by acquisition systems and FFT transform can be subject of uncontrolled errors because of intrinsic properties of Fourier transform. The paper proposes a correction method based on the best evaluation of the fundamental frequency and calculation of the fundamental RMS for voltage and current as well as their phase by using the definitions of these quantities. To validate the method we made virtual experiments on generated signals and laboratory measurements with different forms of currents obtained by feeding the circuits with different voltages. There is a good agreement of measurements and calculated values.
{"title":"Measuring active power for a converter fed induction machine","authors":"I. Soran, I. Sztojanov","doi":"10.1109/DEMPED.2005.4662498","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662498","url":null,"abstract":"The power measurement by acquisition systems and FFT transform can be subject of uncontrolled errors because of intrinsic properties of Fourier transform. The paper proposes a correction method based on the best evaluation of the fundamental frequency and calculation of the fundamental RMS for voltage and current as well as their phase by using the definitions of these quantities. To validate the method we made virtual experiments on generated signals and laboratory measurements with different forms of currents obtained by feeding the circuits with different voltages. There is a good agreement of measurements and calculated values.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129981004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662546
H. M. Kelk, H. Toliyat
This paper presents a new approach to detect broken rotor bars in cage induction motors. This approach is based on an open terminal test. After disconnecting the motor from the mains, rotor currents will induce voltages in the stator windings. The integral of these voltages that are proportional to the air gap flux of the motor will be used to study the rotor condition. Experimental results are provided to validate the theoretical findings.
{"title":"A new open terminal test approach for broken rotor bar detection in cage induction motors","authors":"H. M. Kelk, H. Toliyat","doi":"10.1109/DEMPED.2005.4662546","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662546","url":null,"abstract":"This paper presents a new approach to detect broken rotor bars in cage induction motors. This approach is based on an open terminal test. After disconnecting the motor from the mains, rotor currents will induce voltages in the stator windings. The integral of these voltages that are proportional to the air gap flux of the motor will be used to study the rotor condition. Experimental results are provided to validate the theoretical findings.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132610312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662524
M.M. Kubo, E. R. Filho
The non-inclusion of the air-gap irregularities in the three-phase induction machine dynamic model causes the elimination of the electromagnetic torque oscillation around a mean value. Usually this phenomenon is due to the rotor eccentricity. In this paper it supposes that the rotor presents elliptical or egg-shaped form as it really happens. In this regard, it is proposed an analytical formulation of the phenomenon and this formulation is extended also to the analysis of non-circularities in the stator surface. Experimental results are compared with simulated ones. From those results it was verified that the developed model can reproduce with good accuracy the oscillation of the electromagnetic torque.
{"title":"Three-phase induction motor dynamic mathematical model considering air-gap irregularities","authors":"M.M. Kubo, E. R. Filho","doi":"10.1109/DEMPED.2005.4662524","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662524","url":null,"abstract":"The non-inclusion of the air-gap irregularities in the three-phase induction machine dynamic model causes the elimination of the electromagnetic torque oscillation around a mean value. Usually this phenomenon is due to the rotor eccentricity. In this paper it supposes that the rotor presents elliptical or egg-shaped form as it really happens. In this regard, it is proposed an analytical formulation of the phenomenon and this formulation is extended also to the analysis of non-circularities in the stator surface. Experimental results are compared with simulated ones. From those results it was verified that the developed model can reproduce with good accuracy the oscillation of the electromagnetic torque.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"2010 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121329760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662521
G. Buja, R. Menis
The direct torque control (DTC) of an induction motor drive carries out the closed-loop control of the stator flux magnitude and the motor torque. The feedback values are estimated by processing the inverter dc-link voltage and the stator currents through the motor voltage model. Any error in the model parameter (i.e. the stator resistance) and in transducing voltage and currents yields an incorrect estimation of the controlled variables, thus altering the drive operation. In this paper the various errors are considered and their effect on the drive operation is studied analytically. The study shows that some errors lead to instability of the drive whilst some others deteriorate its steady-state performance. The theoretical findings are substantiated by experimental results.
{"title":"Effect of parameter and sensing errors on DTC IM drive operation","authors":"G. Buja, R. Menis","doi":"10.1109/DEMPED.2005.4662521","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662521","url":null,"abstract":"The direct torque control (DTC) of an induction motor drive carries out the closed-loop control of the stator flux magnitude and the motor torque. The feedback values are estimated by processing the inverter dc-link voltage and the stator currents through the motor voltage model. Any error in the model parameter (i.e. the stator resistance) and in transducing voltage and currents yields an incorrect estimation of the controlled variables, thus altering the drive operation. In this paper the various errors are considered and their effect on the drive operation is studied analytically. The study shows that some errors lead to instability of the drive whilst some others deteriorate its steady-state performance. The theoretical findings are substantiated by experimental results.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114233288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662528
C. Sumereder, R. Woschitz, M. Muhr
The condition evaluation of electric power equipment gained very much importance in the last years. Generally it forms the basis of maintenance strategy, risk evaluation and the decision over renewal or reinvestment. Dielectric measurements are a very important tool for the technical diagnosis of electric insulation systems like generator bars of rotating machines. Beside partial discharge and dissipation factor measurements the dielectric response of the electrical insulation system gives further information about the aging process and the condition of the insulation medium. The measurements and analysis of the polarization and depolarization current (PDC) are done in time domain and for the interpretation of the test results in the frequency domain the discrete Fourier transformation is applied. This paper should give a view to conventional dielectric measurements and the PDC analysis at insulation systems for rotating machines. Generator bars in resin rich and VPI technology were tested in different stadiums of age, mode of operation and load. For the results of the practical tests a mathematical model was found to show the correspondence to the existing models of the classical equivalent circuit of parallel and serial resistances and capacitances.
{"title":"Condition evaluation of generator bars","authors":"C. Sumereder, R. Woschitz, M. Muhr","doi":"10.1109/DEMPED.2005.4662528","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662528","url":null,"abstract":"The condition evaluation of electric power equipment gained very much importance in the last years. Generally it forms the basis of maintenance strategy, risk evaluation and the decision over renewal or reinvestment. Dielectric measurements are a very important tool for the technical diagnosis of electric insulation systems like generator bars of rotating machines. Beside partial discharge and dissipation factor measurements the dielectric response of the electrical insulation system gives further information about the aging process and the condition of the insulation medium. The measurements and analysis of the polarization and depolarization current (PDC) are done in time domain and for the interpretation of the test results in the frequency domain the discrete Fourier transformation is applied. This paper should give a view to conventional dielectric measurements and the PDC analysis at insulation systems for rotating machines. Generator bars in resin rich and VPI technology were tested in different stadiums of age, mode of operation and load. For the results of the practical tests a mathematical model was found to show the correspondence to the existing models of the classical equivalent circuit of parallel and serial resistances and capacitances.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"159 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133490559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662513
H. Kapeller, C. Kral, F. Pirker, G. Pascoli
Stator winding failures are a serious problem of induction machines. In the case of bearing failures or rotor faults, fault-specific signatures increase slowly. An induction machine with such failures still can be operated for a certain time without taking strict precautions. Stator faults may occur much faster due to insulation breakdown or overload and are therefore more critical with respect to time. This paper presents measurement results of an accidentally arising stator winding fault, which was recorded during the investigation of stator asymmetries. Furthermore, an on-line fault detection technique as well as some measurement data applied to this technique, are presented. The used technique is based on extracting a so called injected negative sequence current.
{"title":"Stator winding turn fault detection for induction machines","authors":"H. Kapeller, C. Kral, F. Pirker, G. Pascoli","doi":"10.1109/DEMPED.2005.4662513","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662513","url":null,"abstract":"Stator winding failures are a serious problem of induction machines. In the case of bearing failures or rotor faults, fault-specific signatures increase slowly. An induction machine with such failures still can be operated for a certain time without taking strict precautions. Stator faults may occur much faster due to insulation breakdown or overload and are therefore more critical with respect to time. This paper presents measurement results of an accidentally arising stator winding fault, which was recorded during the investigation of stator asymmetries. Furthermore, an on-line fault detection technique as well as some measurement data applied to this technique, are presented. The used technique is based on extracting a so called injected negative sequence current.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"325 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133950574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-09-01DOI: 10.1109/DEMPED.2005.4662493
I. Jaksch, P. Fuchs
Space transformation transfers 3 phase currents to one space (Parkpsilas) vector. Frequency component of space vector magnitude MagP2fl at 2fl is the basic diagnostic symptom. In the paper the analysis of possible cause of 3-phase current system unbalance due to stator faults are discussed and it is shown, that stator faults induce amplitude, phase or harmonic distortion unbalance. By comparing the measured and computed values of MagP2fl only for one of three cause of unbalance we can ascertain the contribution of individual influences to overall unbalance. MagP2fl is influenced both by stator faults and unfortunately also the overall state of 3-phase feeding system which itself can be unbalanced and causes additional error. Experiments were made at motors with artificially evoked faults of various sizes and severity simulating short winding in phase and simulating increasing stator winding resistance and their relations to values of MagP2fl examined for various motor loads. The influence of fed system on MagP2fl was searched by measurement the same stator faults for mains fed and inverter fed motors and correction for unbalanced fed system was proposed to ensure exact determination of diagnostic symptom. For the determination of degree of fault severity and for the comparison of stator fault for various induction motors the normalization coefficient is proposed.
{"title":"Using space transformation for exact diagnostic of induction motor stator faults","authors":"I. Jaksch, P. Fuchs","doi":"10.1109/DEMPED.2005.4662493","DOIUrl":"https://doi.org/10.1109/DEMPED.2005.4662493","url":null,"abstract":"Space transformation transfers 3 phase currents to one space (Parkpsilas) vector. Frequency component of space vector magnitude MagP2fl at 2fl is the basic diagnostic symptom. In the paper the analysis of possible cause of 3-phase current system unbalance due to stator faults are discussed and it is shown, that stator faults induce amplitude, phase or harmonic distortion unbalance. By comparing the measured and computed values of MagP2fl only for one of three cause of unbalance we can ascertain the contribution of individual influences to overall unbalance. MagP2fl is influenced both by stator faults and unfortunately also the overall state of 3-phase feeding system which itself can be unbalanced and causes additional error. Experiments were made at motors with artificially evoked faults of various sizes and severity simulating short winding in phase and simulating increasing stator winding resistance and their relations to values of MagP2fl examined for various motor loads. The influence of fed system on MagP2fl was searched by measurement the same stator faults for mains fed and inverter fed motors and correction for unbalanced fed system was proposed to ensure exact determination of diagnostic symptom. For the determination of degree of fault severity and for the comparison of stator fault for various induction motors the normalization coefficient is proposed.","PeriodicalId":230148,"journal":{"name":"2005 5th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134269626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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