Pub Date : 2016-10-01DOI: 10.1109/HOLM.2016.7780014
R. Malucci
This paper provides an analysis of the current density distribution in a single circular contact spot for cases that represents geometrical configurations that are closer to what occurs in real contacting members. In the past, flat contact spots have been used to estimate current density distributions for single circular spots by assuming that bridge conditions do not exist. However, the bridge condition changes the current density at the edge of the contact spot. With no bridge, the mixed boundary conditions for voltage and electric field lie in a plane and give rise to infinite current densities at the edge of the contact spot. In the present paper, when bridge geometries exist, it was found the mixed boundary conditions do not lie in a plane and give rise to finite current densities at the edges. In this work, electromagnetic theory was used to calculate the current density distribution that occurs for bridge geometries. These results are subsequently compared to the traditional results that are often used in analyses and show as the slope of the bridge increases, the current density at the edge decreases to finite values. In addition, it was seen that as the slope increases the current density tends to even out across the contact spot. Consequently, it is seen that the bridge condition at the contact spot may impact the degradation rate for current density driven mechanisms such as electro-migration. In addition, to complete the picture, the impact on average current density in individual spots is reviewed regarding the effects of spot size and position in the contact region.
{"title":"Single and multi-spot current density distribution","authors":"R. Malucci","doi":"10.1109/HOLM.2016.7780014","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780014","url":null,"abstract":"This paper provides an analysis of the current density distribution in a single circular contact spot for cases that represents geometrical configurations that are closer to what occurs in real contacting members. In the past, flat contact spots have been used to estimate current density distributions for single circular spots by assuming that bridge conditions do not exist. However, the bridge condition changes the current density at the edge of the contact spot. With no bridge, the mixed boundary conditions for voltage and electric field lie in a plane and give rise to infinite current densities at the edge of the contact spot. In the present paper, when bridge geometries exist, it was found the mixed boundary conditions do not lie in a plane and give rise to finite current densities at the edges. In this work, electromagnetic theory was used to calculate the current density distribution that occurs for bridge geometries. These results are subsequently compared to the traditional results that are often used in analyses and show as the slope of the bridge increases, the current density at the edge decreases to finite values. In addition, it was seen that as the slope increases the current density tends to even out across the contact spot. Consequently, it is seen that the bridge condition at the contact spot may impact the degradation rate for current density driven mechanisms such as electro-migration. In addition, to complete the picture, the impact on average current density in individual spots is reviewed regarding the effects of spot size and position in the contact region.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134452185","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780023
Fuxi Zhang, G. Flowers, R. Dean, J. Suhling, Jinchun Gao
In the field of electrical contacts, vibration-induced fretting corrosion is a major cause of connector failure. Considerable work has been done in this area, with the main focus being on the effects of transverse vibration on the connector and wire harness set. The present study focuses on fretting corrosion resulting from vibration parallel to the axis of a connector pair. A series of studies, which combined experimental work and parallel modeling/simulation/analysis of a single blade-receptacle pair were conducted to explore driving mechanisms and gain insight into the behavior of connectors exposed to such vibration environments. Experimental results that consider a variety of cable lengths, spring forces and finish type are presented. In addition, modeling results are presented that detail the relative motion at the contact interface resulting from the vibration input levels employed in the experimental testing and provide insight into the physical mechanisms driving the observed fretting.
{"title":"A study on axial vibration-induced fretting corrosion in electrical connector pair","authors":"Fuxi Zhang, G. Flowers, R. Dean, J. Suhling, Jinchun Gao","doi":"10.1109/HOLM.2016.7780023","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780023","url":null,"abstract":"In the field of electrical contacts, vibration-induced fretting corrosion is a major cause of connector failure. Considerable work has been done in this area, with the main focus being on the effects of transverse vibration on the connector and wire harness set. The present study focuses on fretting corrosion resulting from vibration parallel to the axis of a connector pair. A series of studies, which combined experimental work and parallel modeling/simulation/analysis of a single blade-receptacle pair were conducted to explore driving mechanisms and gain insight into the behavior of connectors exposed to such vibration environments. Experimental results that consider a variety of cable lengths, spring forces and finish type are presented. In addition, modeling results are presented that detail the relative motion at the contact interface resulting from the vibration input levels employed in the experimental testing and provide insight into the physical mechanisms driving the observed fretting.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130973623","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780025
P. Slade, E. Taylor
Experimental data for the repulsion or blow-off force FB between closed contacts carrying current were compiled in order to derive an empirical relationship for this force. The data cover a period of 65 years, and includes data from contacts in both air and in vacuum with currents ranging from 1–200 kA peak. Plotting the blow-off force vs. the current reveals a simple relationship independent of the contact material, FB = k· I2, where i is the peak current and k is a constant. This relationship provides a quick estimate of the blow-off force in practical designs for overload and fault currents. It can help guide the selection of the proper contact force to prevent welding, and is very useful in the development of theories calculating the welding current for closed contacts carrying current.
{"title":"The repulsion or blow-off force between closed contacts carrying current","authors":"P. Slade, E. Taylor","doi":"10.1109/HOLM.2016.7780025","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780025","url":null,"abstract":"Experimental data for the repulsion or blow-off force FB between closed contacts carrying current were compiled in order to derive an empirical relationship for this force. The data cover a period of 65 years, and includes data from contacts in both air and in vacuum with currents ranging from 1–200 kA peak. Plotting the blow-off force vs. the current reveals a simple relationship independent of the contact material, FB = k· I2, where i is the peak current and k is a constant. This relationship provides a quick estimate of the blow-off force in practical designs for overload and fault currents. It can help guide the selection of the proper contact force to prevent welding, and is very useful in the development of theories calculating the welding current for closed contacts carrying current.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125682368","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780029
R. Boukadoum, A. Barbet, P. Dessante, R. Landfried, T. Leblanc, P. Teste
In the next few years the electrical power embedded in future aircrafts will strongly increase. The supply voltage will increase to 230 VAC and ± 270 VDC or 540 VDC; thereby studies concerning the embedded equipment behavior must be done. For such power networks characteristics the risk of arc fault and requirements for arc tracking will also increase. The aim of this work is to propose a simple 1D model of a DC short gap electric arc in aeronautical pressure conditions: i.e. a pressure in the range [10 mbar–1 bar] which corresponds to the aircrafts altitudes. By emitting certain assumptions, the approach is to find the temperature distribution in the arc column and deduce from that the characteristics of the arc current as a function of electric field in the column and the maximum temperature in the center of the arc column. The novelty of this work is the observation of the evolution of the temperature (and as a consequence the evolution of the arc current) if we assume that the radius of the arc column is not limited like in wall stabilized arc where the wall is water cooled, the arc radius can expand as much as possible. The study is done in the air.
{"title":"Simple 1D model of a short gap DC electric arc in in aeronautical pressure conditions","authors":"R. Boukadoum, A. Barbet, P. Dessante, R. Landfried, T. Leblanc, P. Teste","doi":"10.1109/HOLM.2016.7780029","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780029","url":null,"abstract":"In the next few years the electrical power embedded in future aircrafts will strongly increase. The supply voltage will increase to 230 VAC and ± 270 VDC or 540 VDC; thereby studies concerning the embedded equipment behavior must be done. For such power networks characteristics the risk of arc fault and requirements for arc tracking will also increase. The aim of this work is to propose a simple 1D model of a DC short gap electric arc in aeronautical pressure conditions: i.e. a pressure in the range [10 mbar–1 bar] which corresponds to the aircrafts altitudes. By emitting certain assumptions, the approach is to find the temperature distribution in the arc column and deduce from that the characteristics of the arc current as a function of electric field in the column and the maximum temperature in the center of the arc column. The novelty of this work is the observation of the evolution of the temperature (and as a consequence the evolution of the arc current) if we assume that the radius of the arc column is not limited like in wall stabilized arc where the wall is water cooled, the arc radius can expand as much as possible. The study is done in the air.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114077401","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780018
M. Hasegawa, S. Tokumitsu
Break operations of AgSnO2 contact pairs were conducted in a DC inductive circuit (L=5.7mH) at 14V-11A and in a DC resistive circuit at 14V-13A under different contact opening speeds from 0.5 to 200 mm/s and with/without external magnetic field application in air. Break arc voltage waveforms were observed, and total break arc durations and metallic phase durations were determined based the observed arc voltage waveforms. After the experiments, averages for total arc durations as well as the metallic phase and gaseous phase (when observed) durations were calculated at each condition. The results show that increases in the contact opening speeds lead to reductions in metallic phase durations, while application of external magnetic field causes gaseous phases to become shorter.
{"title":"Break arc duration characteristics of AgSnO2 contacts under magnetic field application with contact opening speeds in the range up to 200mm/s in DC load conditions","authors":"M. Hasegawa, S. Tokumitsu","doi":"10.1109/HOLM.2016.7780018","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780018","url":null,"abstract":"Break operations of AgSnO2 contact pairs were conducted in a DC inductive circuit (L=5.7mH) at 14V-11A and in a DC resistive circuit at 14V-13A under different contact opening speeds from 0.5 to 200 mm/s and with/without external magnetic field application in air. Break arc voltage waveforms were observed, and total break arc durations and metallic phase durations were determined based the observed arc voltage waveforms. After the experiments, averages for total arc durations as well as the metallic phase and gaseous phase (when observed) durations were calculated at each condition. The results show that increases in the contact opening speeds lead to reductions in metallic phase durations, while application of external magnetic field causes gaseous phases to become shorter.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121650483","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780022
K. Mashimo, S. Yamazaki, Atsushi Shimoyamada, H. Nishikubo, Y. Hori, H. Sasaki
Observations of sliced cross sections after sliding was made with a scanning transmission electron microscope (STEM). The sliced samples were picked from the fretting debris on the surface of specimens. Recently, high-angle annular dark-field STEM (HAADF STEM) technology has been significantly advanced [5-7]. The resolution is sufficiently fine to distinguish sub — angstrom structures, because of the improvement in convergence of electron beam. In dark — field images, the brightness contrast owing to the difference between the masses of two elements is clearly recognized. Thus, the electrical contact resistance after sliding might be estimated based on these observations. The authors have built a three-dimensional resistance-calculation model based on STEM observations. Presently, the observations are two-dimensional; therefore, the three-dimensional structure is built from discrete images with interpolation. The comparison of calculations and measurements is agreeable. The oxygen vacancies in SnO2 cannot be directly measured because of its low density. Though we can obtain the consistency of vacancies from the measurement of carrier density indirectly, this still adds uncertainty to the contact resistance simulation [4].
{"title":"Microstructure of fretting debris on tin-plated terminals","authors":"K. Mashimo, S. Yamazaki, Atsushi Shimoyamada, H. Nishikubo, Y. Hori, H. Sasaki","doi":"10.1109/HOLM.2016.7780022","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780022","url":null,"abstract":"Observations of sliced cross sections after sliding was made with a scanning transmission electron microscope (STEM). The sliced samples were picked from the fretting debris on the surface of specimens. Recently, high-angle annular dark-field STEM (HAADF STEM) technology has been significantly advanced [5-7]. The resolution is sufficiently fine to distinguish sub — angstrom structures, because of the improvement in convergence of electron beam. In dark — field images, the brightness contrast owing to the difference between the masses of two elements is clearly recognized. Thus, the electrical contact resistance after sliding might be estimated based on these observations. The authors have built a three-dimensional resistance-calculation model based on STEM observations. Presently, the observations are two-dimensional; therefore, the three-dimensional structure is built from discrete images with interpolation. The comparison of calculations and measurements is agreeable. The oxygen vacancies in SnO2 cannot be directly measured because of its low density. Though we can obtain the consistency of vacancies from the measurement of carrier density indirectly, this still adds uncertainty to the contact resistance simulation [4].","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117068359","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780031
Xiaohan Zhang, Yang Xu, R. Jackson
This work studies the fractal dimensions of rough surfaces as calculated by several existing methods on measured and generated surface profiles. Two methods for generating rough surfaces are used in this work. The first one is to reconstruct the rough surface through the inverse Fourier transform based on a prescribed Power Spectrum Density (PSD) and the other one is using the Weierstrass-Mandelbrot (W-M) function. The fractal dimension values of all the rough surfaces are calculated by four different methods, namely, (1) the box-counting method, (2) the roughness-length method, (3) the power spectral density method and (4) the variogram method. Then the results from these four methods are compared. Since fractal surfaces are always clarified either as self-similar (the scaling ratio is the same in all directions) or as self-affine (scaling ratio varies in prescribed fashion over scales), it can be found that the fractal dimension values are not the same after analyzing the generated self-similar rough surfaces by these two methods. The fractal dimension values for real rough surfaces, as well as other parameters, are also calculated by four different methods. The analysis indicates that real rough surfaces are not easily represented as perfect fractals as researchers and engineers often assume.
{"title":"An analysis of generated fractal and measured rough surfaces","authors":"Xiaohan Zhang, Yang Xu, R. Jackson","doi":"10.1109/HOLM.2016.7780031","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780031","url":null,"abstract":"This work studies the fractal dimensions of rough surfaces as calculated by several existing methods on measured and generated surface profiles. Two methods for generating rough surfaces are used in this work. The first one is to reconstruct the rough surface through the inverse Fourier transform based on a prescribed Power Spectrum Density (PSD) and the other one is using the Weierstrass-Mandelbrot (W-M) function. The fractal dimension values of all the rough surfaces are calculated by four different methods, namely, (1) the box-counting method, (2) the roughness-length method, (3) the power spectral density method and (4) the variogram method. Then the results from these four methods are compared. Since fractal surfaces are always clarified either as self-similar (the scaling ratio is the same in all directions) or as self-affine (scaling ratio varies in prescribed fashion over scales), it can be found that the fractal dimension values are not the same after analyzing the generated self-similar rough surfaces by these two methods. The fractal dimension values for real rough surfaces, as well as other parameters, are also calculated by four different methods. The analysis indicates that real rough surfaces are not easily represented as perfect fractals as researchers and engineers often assume.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128864192","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780021
Song-Zhu Kure-Chu, Rie Nakagawa, T. Ogasawara, H. Yashiro, S. Sawada, A. Shimizu, Y. Saitoh
This study is aimed at clarifying the mechanism of wear process for Ag plating through a one-way sliding wear test. The samples of different hardness Ag plating on copper alloys were prepared as coupon and embossment specimens, which simulated terminal contacts. During the sliding test, the contact resistance and the friction coefficient are measured. The surface and cross-section morphologies, roughness, tribo-film formation, and wear volume of the Ag films after wear tests were investigated and the wear mechanism was discussed. As results, the hard Ag plating film (120 Hv) exhibited higher contact resistance comparing to the soft Ag plating film (80 Hv). The soft Ag film delivered a larger wear scar on embossment and wider wear trace on coupon specimens compared to the hard one. The overall wear volume of hard Ag film was less than that of soft Ag film, which can be attributed to the fine crystalline structure of hard Ag. Moreover, the observation of tribofilms formed on the Ag films after wear tests suggested that a mixed-type of adhesive and abrasive wears occurred for both of soft and hard Ag films.
{"title":"Sliding friction, wear and tribofilm formation of silver films electro-plated on copper alloy sheets","authors":"Song-Zhu Kure-Chu, Rie Nakagawa, T. Ogasawara, H. Yashiro, S. Sawada, A. Shimizu, Y. Saitoh","doi":"10.1109/HOLM.2016.7780021","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780021","url":null,"abstract":"This study is aimed at clarifying the mechanism of wear process for Ag plating through a one-way sliding wear test. The samples of different hardness Ag plating on copper alloys were prepared as coupon and embossment specimens, which simulated terminal contacts. During the sliding test, the contact resistance and the friction coefficient are measured. The surface and cross-section morphologies, roughness, tribo-film formation, and wear volume of the Ag films after wear tests were investigated and the wear mechanism was discussed. As results, the hard Ag plating film (120 Hv) exhibited higher contact resistance comparing to the soft Ag plating film (80 Hv). The soft Ag film delivered a larger wear scar on embossment and wider wear trace on coupon specimens compared to the hard one. The overall wear volume of hard Ag film was less than that of soft Ag film, which can be attributed to the fine crystalline structure of hard Ag. Moreover, the observation of tribofilms formed on the Ag films after wear tests suggested that a mixed-type of adhesive and abrasive wears occurred for both of soft and hard Ag films.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114957433","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780027
Cui Xinglei, Z. Xue, Chen Mo, Luo Fu-biao, Zhou Zhefeng
Electrical lifespan prediction has always been one of the greatest challenges in switching apparatus. In this paper, a mathematical model based on arc charge accumulation from experiments is set up to predict the electrical lifespan of high-voltage direct-current (HVDC) relays. The electrical circuit condition is 270VDC/200A, resistive load. The contact pair is bridge-type and made of copper. Experiments are carried out with a parameter-adjustable device in similar with actual HVDC relay structure. The magnetic field flux density for arc blowing is controlled in the range of 40mT to 80mT. The arc current waveforms are acquired and the arc charge during each breaking operation is calculated. The arc charge is accumulated until it reaches threshold value, which is decided according to electrical lifespan test results of actual products. The relationship between the lifespan and the magnetic field flux density is constructed, which can be used for lifespan prediction.
{"title":"Electrical lifespan prediction of high-voltage direct-current relay based on arc charge accumulation","authors":"Cui Xinglei, Z. Xue, Chen Mo, Luo Fu-biao, Zhou Zhefeng","doi":"10.1109/HOLM.2016.7780027","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780027","url":null,"abstract":"Electrical lifespan prediction has always been one of the greatest challenges in switching apparatus. In this paper, a mathematical model based on arc charge accumulation from experiments is set up to predict the electrical lifespan of high-voltage direct-current (HVDC) relays. The electrical circuit condition is 270VDC/200A, resistive load. The contact pair is bridge-type and made of copper. Experiments are carried out with a parameter-adjustable device in similar with actual HVDC relay structure. The magnetic field flux density for arc blowing is controlled in the range of 40mT to 80mT. The arc current waveforms are acquired and the arc charge during each breaking operation is calculated. The arc charge is accumulated until it reaches threshold value, which is decided according to electrical lifespan test results of actual products. The relationship between the lifespan and the magnetic field flux density is constructed, which can be used for lifespan prediction.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115115884","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 : 2016-10-01DOI: 10.1109/HOLM.2016.7780017
Jianyu Qu, Xingwen Li, Qian Wang
Due to the structure of multiple movable contacts in parallel in Air circuit breakers, the outer movable contacts tilt seriously when enduring the large short-circuit current. This paper is aimed to investigate the resistance of the tilted contact. A new designed experimental setup is built. Especially, the tilt angle and the contact force are able to be adjusted. Based on the measured results, it is found that the contact resistance is increased seriously when the movable contact starts tilting. After the contact type changing from the line contact to the point contact and the contact center offsetting to the edge of the movable contact, the contact resistance is increased gently with the tilt angle. At that time, the contact resistance is about 2.8 times of that without tilting, in the case that the contact materials are AgW50 and AgNi30, and the contact force is 105N.
{"title":"Experimental study on electric resistance of tilted contact in air circuit breaker","authors":"Jianyu Qu, Xingwen Li, Qian Wang","doi":"10.1109/HOLM.2016.7780017","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780017","url":null,"abstract":"Due to the structure of multiple movable contacts in parallel in Air circuit breakers, the outer movable contacts tilt seriously when enduring the large short-circuit current. This paper is aimed to investigate the resistance of the tilted contact. A new designed experimental setup is built. Especially, the tilt angle and the contact force are able to be adjusted. Based on the measured results, it is found that the contact resistance is increased seriously when the movable contact starts tilting. After the contact type changing from the line contact to the point contact and the contact center offsetting to the edge of the movable contact, the contact resistance is increased gently with the tilt angle. At that time, the contact resistance is about 2.8 times of that without tilting, in the case that the contact materials are AgW50 and AgNi30, and the contact force is 105N.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122437499","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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