Pub Date : 1993-09-27DOI: 10.1109/HOLM.1993.489674
E.W. Glossbrenner
The A-spot, or groups of A-spots, are fundamental to the electrical and mechanical performance of all electrical contacts. It is only through the observance of the behavior of sliding contacts which are uniquely critical for static and dynamic contact resistance, friction, and extended wear, can the role of the A-spots be seen. A scenario for sliding contact behavior has been developed based largely on information gleaned from papers presented at the Holm Conference and four decades of practical experience in addressing problems with sliding contacts in slip ring assemblies.
{"title":"The life and times of an A-spot-a tutorial on sliding contacts","authors":"E.W. Glossbrenner","doi":"10.1109/HOLM.1993.489674","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489674","url":null,"abstract":"The A-spot, or groups of A-spots, are fundamental to the electrical and mechanical performance of all electrical contacts. It is only through the observance of the behavior of sliding contacts which are uniquely critical for static and dynamic contact resistance, friction, and extended wear, can the role of the A-spots be seen. A scenario for sliding contact behavior has been developed based largely on information gleaned from papers presented at the Holm Conference and four decades of practical experience in addressing problems with sliding contacts in slip ring assemblies.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80523144","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 : 1993-09-27DOI: 10.1109/HOLM.1993.489685
M. Braunovic, N. Aleksandrov
The effect of electrical current on the morphology and kinetics of formation of intermetallic compounds of bimetallic friction welded aluminum-copper joints was studied. The formation and growth of intermetallic compounds was studied in the temperature ranges 200-500/spl deg/C that was realized by heating Al-Cu joints with an AC current of different intensities (400-1000 A). The presence of an electrical field greatly accelerates the kinetics of formation of intermetallic phases and alters significantly their morphology. The formation and growth of intermetallic phases exerts a pronounced effect on the mechanical (microhardness) and electrical integrity of aluminum-copper joints. The contact resistance increases linearly with the thickness of the intermetallics. The phases formed are very hard and extremely brittle. The growth kinetics of intermetallic phases under the influence of electrical current is much higher than that under diffusion annealing in furnace.
{"title":"Effect of electrical current on the morphology and kinetics of formation of intermetallic phases in bimetallic aluminum-copper joints","authors":"M. Braunovic, N. Aleksandrov","doi":"10.1109/HOLM.1993.489685","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489685","url":null,"abstract":"The effect of electrical current on the morphology and kinetics of formation of intermetallic compounds of bimetallic friction welded aluminum-copper joints was studied. The formation and growth of intermetallic compounds was studied in the temperature ranges 200-500/spl deg/C that was realized by heating Al-Cu joints with an AC current of different intensities (400-1000 A). The presence of an electrical field greatly accelerates the kinetics of formation of intermetallic phases and alters significantly their morphology. The formation and growth of intermetallic phases exerts a pronounced effect on the mechanical (microhardness) and electrical integrity of aluminum-copper joints. The contact resistance increases linearly with the thickness of the intermetallics. The phases formed are very hard and extremely brittle. The growth kinetics of intermetallic phases under the influence of electrical current is much higher than that under diffusion annealing in furnace.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77251494","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 : 1993-09-27DOI: 10.1109/HOLM.1993.489683
K. Niizuma, M. Hasegawa
Arc discharge between contact electrodes brings material transfer and erosion, which sometimes cause serious contact failure. To achieve better reliability and longer life of electromechanical components, characteristics of material transfer and arc erosion of each contact material under different load conditions have to be studied. However, no effective methods for gathering numerical 3D information on contact surfaces have been available. In this paper, the theory and system of a scanning laser microscope is explained, which is confirmed to be useful equipment for this purpose. A confocal optical system and a focus scan memory of the equipment enable us to measure depth of craters and height of pips on contact surfaces in a short time without damaging specimens. By processing the measured data with an image-data processing software, 3D images of contact surfaces are displayed and volume of craters and pips is easily calculated. Relay contact surfaces operated in a capacitive load circuit are numerically evaluated with the scanning laser microscope. The 3D data such as height, depth and volume of craters and pips are measured and material transfer rate per unit arc energy is calculated. The results are shown to confirm how useful the equipment is for investigation of electrical contacts.
{"title":"Evaluation of contact surface configuration with a scanning laser microscope","authors":"K. Niizuma, M. Hasegawa","doi":"10.1109/HOLM.1993.489683","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489683","url":null,"abstract":"Arc discharge between contact electrodes brings material transfer and erosion, which sometimes cause serious contact failure. To achieve better reliability and longer life of electromechanical components, characteristics of material transfer and arc erosion of each contact material under different load conditions have to be studied. However, no effective methods for gathering numerical 3D information on contact surfaces have been available. In this paper, the theory and system of a scanning laser microscope is explained, which is confirmed to be useful equipment for this purpose. A confocal optical system and a focus scan memory of the equipment enable us to measure depth of craters and height of pips on contact surfaces in a short time without damaging specimens. By processing the measured data with an image-data processing software, 3D images of contact surfaces are displayed and volume of craters and pips is easily calculated. Relay contact surfaces operated in a capacitive load circuit are numerically evaluated with the scanning laser microscope. The 3D data such as height, depth and volume of craters and pips are measured and material transfer rate per unit arc energy is calculated. The results are shown to confirm how useful the equipment is for investigation of electrical contacts.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79414989","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 : 1993-09-27DOI: 10.1109/HOLM.1993.489655
V. Behrens, T. Honig, A. Kraus, Roland Michal, K. E. Saeger, Rainer Schmidberger, T. Staneff
A new silver/tin oxide contact material is presented which is based on the utilization of tin oxide powders produced with the aid of the so-called "spray roasting" or "reaction spray" process. The contact properties of this new material were tested in a model switch as well as in commercially available contactors of different sizes and designs. The investigations carried out comprise tests of service life for different utilization categories, thermal behavior under continuous current, and welding on make. It was found, that by varying additives and production parameters in the "reaction spray" process for the tin oxide powders contact materials can be produced, which are superior in performance to conventionally manufactured p.m. type silver/tin oxide materials.
{"title":"An advanced silver/tin oxide contact material","authors":"V. Behrens, T. Honig, A. Kraus, Roland Michal, K. E. Saeger, Rainer Schmidberger, T. Staneff","doi":"10.1109/HOLM.1993.489655","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489655","url":null,"abstract":"A new silver/tin oxide contact material is presented which is based on the utilization of tin oxide powders produced with the aid of the so-called \"spray roasting\" or \"reaction spray\" process. The contact properties of this new material were tested in a model switch as well as in commercially available contactors of different sizes and designs. The investigations carried out comprise tests of service life for different utilization categories, thermal behavior under continuous current, and welding on make. It was found, that by varying additives and production parameters in the \"reaction spray\" process for the tin oxide powders contact materials can be produced, which are superior in performance to conventionally manufactured p.m. type silver/tin oxide materials.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74809636","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 : 1993-09-27DOI: 10.1109/HOLM.1993.489654
E. Hetzmannseder, W. Rieder
The influence of the bounce parameters (bounce arc duration, bounce height and static contact force, current and magnetic induction) on the make only erosion was investigated by systematic variation of each single parameter value in a bounce model switch. The model switch simulates bounces occurring in modern contactors. Ag/SnO/sub 2/ suffered either three times higher or about 50% lower erosion losses than Ag/CdO depending on the manufacturing process (internally oxidized, powder metallurgically produced) and/or the additives of the materials, and therefore on the structure of the materials rather than on the kind of metal oxide component (CdO or SnO/sub 2/). The different make erosion rates of the materials investigated have been correlated with the micro structure of their stressed surfaces.
{"title":"The influence of bounce parameters on the make erosion of silver/metal-oxide contact materials","authors":"E. Hetzmannseder, W. Rieder","doi":"10.1109/HOLM.1993.489654","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489654","url":null,"abstract":"The influence of the bounce parameters (bounce arc duration, bounce height and static contact force, current and magnetic induction) on the make only erosion was investigated by systematic variation of each single parameter value in a bounce model switch. The model switch simulates bounces occurring in modern contactors. Ag/SnO/sub 2/ suffered either three times higher or about 50% lower erosion losses than Ag/CdO depending on the manufacturing process (internally oxidized, powder metallurgically produced) and/or the additives of the materials, and therefore on the structure of the materials rather than on the kind of metal oxide component (CdO or SnO/sub 2/). The different make erosion rates of the materials investigated have been correlated with the micro structure of their stressed surfaces.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72826069","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 : 1993-09-27DOI: 10.1109/HOLM.1993.489681
X. Zhou, J. Heberlein, E. Pfender
We have previously reported results of a theoretical study which predict that high current arc cathode erosion is predominantly dependent on the work function and the vapor pressure of the cathode material, and that the thermal design plays a secondary role. These results have been obtained with a newly developed self-consistent model of the cathode region including a realistic one-dimensional sheath model. The results have been obtained for an argon arc and a tungsten cathode. The model has now been extended and results have been obtained for different arc gases and different electrode materials. The arc gas has a strong effect because it affects not only the temperature at the boundary between the arc and the cathode region, but also the electron density in the cathode region and at the cathode. The results of the calculations show that the cathode material plays a dominant role in terms of the cathode spot temperature and the associated mass loss rate by evaporation of cathode material. Since the addition of thorium oxide to tungsten reduces the work function of the cathode material, the cathode spot temperature as well as the mass loss rate by evaporation are reduced. For the same cathode material, hydrogen leads to the highest cathode spot temperature and mass loss rate, followed by nitrogen and argon. The current density at the cathode spot, the cathode spot size, and the percentages of the energy fluxes removed from the cathode spot are mainly determined by the plasma gas rather than by the cathode material.
{"title":"Model predictions of arc cathode erosion rate dependence on plasma gas and on cathode material","authors":"X. Zhou, J. Heberlein, E. Pfender","doi":"10.1109/HOLM.1993.489681","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489681","url":null,"abstract":"We have previously reported results of a theoretical study which predict that high current arc cathode erosion is predominantly dependent on the work function and the vapor pressure of the cathode material, and that the thermal design plays a secondary role. These results have been obtained with a newly developed self-consistent model of the cathode region including a realistic one-dimensional sheath model. The results have been obtained for an argon arc and a tungsten cathode. The model has now been extended and results have been obtained for different arc gases and different electrode materials. The arc gas has a strong effect because it affects not only the temperature at the boundary between the arc and the cathode region, but also the electron density in the cathode region and at the cathode. The results of the calculations show that the cathode material plays a dominant role in terms of the cathode spot temperature and the associated mass loss rate by evaporation of cathode material. Since the addition of thorium oxide to tungsten reduces the work function of the cathode material, the cathode spot temperature as well as the mass loss rate by evaporation are reduced. For the same cathode material, hydrogen leads to the highest cathode spot temperature and mass loss rate, followed by nitrogen and argon. The current density at the cathode spot, the cathode spot size, and the percentages of the energy fluxes removed from the cathode spot are mainly determined by the plasma gas rather than by the cathode material.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81825967","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 : 1993-09-27DOI: 10.1109/HOLM.1993.489673
E. Smith, R. Lysonski, A. Klein, J.W. Agopovich, B. Reed, R. Denton
As part of a program to improve overall performance, a study was undertaken to evaluate forty potential replacement alloys for either the brush or ring members of a slip ring assembly. A reciprocating crossed rod technique was employed to monitor friction coefficient, electrical noise, and relative wear. Tests were performed in air and two candidate fill fluids. Initially, all the alloys were tested as potential brush replacements. These tests were run with the brush alloys riding against a hard gold electroplate (typical of the current materials). Based on these initial results, seven of the alloys were selected as potential ring replacements. Each of the candidate ring alloys was then tested against ten potential brush materials. A numeric rating system was developed which considered changes in wear, noise, and friction. A number of the candidate alloys were selected for additional longer term testing in actual slip ring hardware.
{"title":"Screening contact materials for low speed slip ring assemblies","authors":"E. Smith, R. Lysonski, A. Klein, J.W. Agopovich, B. Reed, R. Denton","doi":"10.1109/HOLM.1993.489673","DOIUrl":"https://doi.org/10.1109/HOLM.1993.489673","url":null,"abstract":"As part of a program to improve overall performance, a study was undertaken to evaluate forty potential replacement alloys for either the brush or ring members of a slip ring assembly. A reciprocating crossed rod technique was employed to monitor friction coefficient, electrical noise, and relative wear. Tests were performed in air and two candidate fill fluids. Initially, all the alloys were tested as potential brush replacements. These tests were run with the brush alloys riding against a hard gold electroplate (typical of the current materials). Based on these initial results, seven of the alloys were selected as potential ring replacements. Each of the candidate ring alloys was then tested against ten potential brush materials. A numeric rating system was developed which considered changes in wear, noise, and friction. A number of the candidate alloys were selected for additional longer term testing in actual slip ring hardware.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91055846","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 : 1993-01-01DOI: 10.1109/holm.1993.489650
B. Malucci, X. Zhou, J. Heberlein, E. Pfender, R. Kothari, R. Vook, R. Timsit, M. Runde, E. Hodne, B. Tatdal
The Holm Conference Prize Paper Award was established in 1970. At that time, the Conference Steering Committee recognized that at each Conference there was at least one paper that stood out from the others in its technical content and quality of presentation. Therefore, the Prize Paper Award Committee was established. The Committee’s purpose is to review each paper, listen to each presentation and then judge which paper should receive the Prize Paper Award. The award is presented to the authors of the Prize Paper at the following year’s Holm Conference.
{"title":"The Holm Conference Prize Paper Award","authors":"B. Malucci, X. Zhou, J. Heberlein, E. Pfender, R. Kothari, R. Vook, R. Timsit, M. Runde, E. Hodne, B. Tatdal","doi":"10.1109/holm.1993.489650","DOIUrl":"https://doi.org/10.1109/holm.1993.489650","url":null,"abstract":"The Holm Conference Prize Paper Award was established in 1970. At that time, the Conference Steering Committee recognized that at each Conference there was at least one paper that stood out from the others in its technical content and quality of presentation. Therefore, the Prize Paper Award Committee was established. The Committee’s purpose is to review each paper, listen to each presentation and then judge which paper should receive the Prize Paper Award. The award is presented to the authors of the Prize Paper at the following year’s Holm Conference.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1993-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84710923","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：