Pub Date : 1900-01-01DOI: 10.1109/HOLM.1991.170807
R.W. Caven, J. Jalali
Develops a personal computer model that predicts contact resistance distributions for clean electrical contacts. The authors describe the modeling technique in detail and compare model prediction with laboratory results. The model takes an approach that integrates contact theory with Monte Carlo simulation. The surface asperities are spherically shaped and randomly distributed over the contact surface, and have heights that follow a Gaussian distribution. The model predicts the mean resistance of a gold butt contact reasonably well. The largest error was 0.2 m Omega at a 1.0-N contact force.<>
开发个人计算机模型，预测清洁电触点的接触电阻分布。作者详细描述了建模技术，并将模型预测与实验室结果进行了比较。该模型采用了接触理论与蒙特卡罗仿真相结合的方法。表面凹凸不平是球形的，随机分布在接触面上，其高度遵循高斯分布。该模型较好地预测了金对接接触的平均电阻。在1.0 n的接触力下，最大误差为0.2 m ω
{"title":"Predicting the contact resistance distribution of electrical contacts by modeling the contact interface","authors":"R.W. Caven, J. Jalali","doi":"10.1109/HOLM.1991.170807","DOIUrl":"https://doi.org/10.1109/HOLM.1991.170807","url":null,"abstract":"Develops a personal computer model that predicts contact resistance distributions for clean electrical contacts. The authors describe the modeling technique in detail and compare model prediction with laboratory results. The model takes an approach that integrates contact theory with Monte Carlo simulation. The surface asperities are spherically shaped and randomly distributed over the contact surface, and have heights that follow a Gaussian distribution. The model predicts the mean resistance of a gold butt contact reasonably well. The largest error was 0.2 m Omega at a 1.0-N contact force.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"117 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131540721","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 : 1900-01-01DOI: 10.1109/HOLM.1991.170808
R. Malucci
A statistical model was developed to characterize surface profiles and calculate the density of contact spots produced when rough surfaces are pressed together. This model incorporates contact force, microhardness, and real and apparent contact area as parameters which can be varied. The effects these variables have on the number of contact spots and asperity deformation were calculated. These results were subsequently used to evaluate the impact on electrical performance of aged contacts. This was accomplished using a previously developed degradation model that utilizes the concept of a third level of constriction to simulate aging. The results indicate that both contact force and geometry play important roles in the electrical performance of aging contacts. The connection between geometry and apparent pressure was estimated using Hertz theory and indicates that one pressure can also be viewed as an important variable.<>
{"title":"Dynamic model of stationary contacts based on random variations of surface characteristics","authors":"R. Malucci","doi":"10.1109/HOLM.1991.170808","DOIUrl":"https://doi.org/10.1109/HOLM.1991.170808","url":null,"abstract":"A statistical model was developed to characterize surface profiles and calculate the density of contact spots produced when rough surfaces are pressed together. This model incorporates contact force, microhardness, and real and apparent contact area as parameters which can be varied. The effects these variables have on the number of contact spots and asperity deformation were calculated. These results were subsequently used to evaluate the impact on electrical performance of aged contacts. This was accomplished using a previously developed degradation model that utilizes the concept of a third level of constriction to simulate aging. The results indicate that both contact force and geometry play important roles in the electrical performance of aging contacts. The connection between geometry and apparent pressure was estimated using Hertz theory and indicates that one pressure can also be viewed as an important variable.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134319278","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}
When Ag contacts were operated in mechanical break-make actions without switching load current in air (laboratory atmosphere), contact resistance increased significantly on about three quarters of the test samples. No contaminant products were detected in the contact area with AES (Auger electron spectroscopy) analysis. However, SEM (scanning electron microscopy) observation revealed an interesting relationship between the contact resistance characteristic and contact surface condition. The samples on which contact resistance increased had a mirror-like plain contact surface, while those with low and stable contact resistance had a rough surface which looked severely damaged by mechanical actions. The contact resistance characteristic was also found to be influenced by measuring current levels and contact force levels. With these experimental results, a possible hypothetical mechanism for the phenomenon is discussed considering the influence of wear types of the electrode surface.<>
{"title":"Significant increase of contact resistance of silver contacts by mechanical switching actions","authors":"M. Hasegawa, T. Yamamota, K. Sawa","doi":"10.1109/33.142892","DOIUrl":"https://doi.org/10.1109/33.142892","url":null,"abstract":"When Ag contacts were operated in mechanical break-make actions without switching load current in air (laboratory atmosphere), contact resistance increased significantly on about three quarters of the test samples. No contaminant products were detected in the contact area with AES (Auger electron spectroscopy) analysis. However, SEM (scanning electron microscopy) observation revealed an interesting relationship between the contact resistance characteristic and contact surface condition. The samples on which contact resistance increased had a mirror-like plain contact surface, while those with low and stable contact resistance had a rough surface which looked severely damaged by mechanical actions. The contact resistance characteristic was also found to be influenced by measuring current levels and contact force levels. With these experimental results, a possible hypothetical mechanism for the phenomenon is discussed considering the influence of wear types of the electrode surface.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133888165","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 : 1900-01-01DOI: 10.1109/HOLM.1991.170801
H. Furtado, P. Mocarzel, V. Silveira
Ag-W contacts were evaluated as to their durability by electrical tests, according the IEC 157-1/73, applying different values of power factor. Such contacts were assembled into 30-A single-pole thermomagnetic circuit breakers. The morphology evolution of the arc affected zone was analyzed after 1000, 3000, and 6000 on/off switching cycles with scanning electron microscopy. Based on these results, the contact performances were compared and the influence of the power factor on the degradation of Ag-W contacts of circuit breakers was established.<>
{"title":"Influence of the power factor on the degradation of Ag-W electrical contact circuit-breakers","authors":"H. Furtado, P. Mocarzel, V. Silveira","doi":"10.1109/HOLM.1991.170801","DOIUrl":"https://doi.org/10.1109/HOLM.1991.170801","url":null,"abstract":"Ag-W contacts were evaluated as to their durability by electrical tests, according the IEC 157-1/73, applying different values of power factor. Such contacts were assembled into 30-A single-pole thermomagnetic circuit breakers. The morphology evolution of the arc affected zone was analyzed after 1000, 3000, and 6000 on/off switching cycles with scanning electron microscopy. Based on these results, the contact performances were compared and the influence of the power factor on the degradation of Ag-W contacts of circuit breakers was established.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115695715","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 : 1900-01-01DOI: 10.1109/HOLM.1991.170806
M. Singer, K. Kshonze
A method for calculating electrical contact resistance utilizing fractal geometry is described. The base model is a modified version of the model of A. Maujamdar and C.L. Tien (1989), which calculates the bulk resistance of a structure of cumulative multilevel asperities. This updated model is then further extended to include the effect of constriction resistance. Two existing models, given by J.A. Greenwood and J.B.P. Williamson (1966), and M.M. Yovanovich (1981), are reviewed and compared numerically to the proposed model. This comparison shows good agreement among the three approaches.<>
{"title":"Electrical resistance of random rough contacting surfaces using fractal surface modeling","authors":"M. Singer, K. Kshonze","doi":"10.1109/HOLM.1991.170806","DOIUrl":"https://doi.org/10.1109/HOLM.1991.170806","url":null,"abstract":"A method for calculating electrical contact resistance utilizing fractal geometry is described. The base model is a modified version of the model of A. Maujamdar and C.L. Tien (1989), which calculates the bulk resistance of a structure of cumulative multilevel asperities. This updated model is then further extended to include the effect of constriction resistance. Two existing models, given by J.A. Greenwood and J.B.P. Williamson (1966), and M.M. Yovanovich (1981), are reviewed and compared numerically to the proposed model. This comparison shows good agreement among the three approaches.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121693904","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 : 1900-01-01DOI: 10.1109/HOLM.1991.170825
N.H. Law, J. Sapjeta, E. S. Sproles
While precious metals such as gold or gold flashed palladium are preferred contact materials for connectors, cost considerations dictate the actual thickness used and hence the corrosion resistance. A method of preventing corrosion on contacts and providing connectors with uniform performance at a minimal cost is desirable. The authors were successful in developing a post-plating surface treatment that provides 0.1- mu m-thick gold contact finishes sufficient protection against 24-hr exposure to a standard mixed gas accelerated test. After the exposure, the contact resistance of 0.1- mu m gold on a nickel substrate is below 50 m Omega , while the same over a matte-finish nickel phosphorus alloy is below 5 m Omega .<>
虽然贵金属如金或金闪钯是连接器的首选接触材料，但成本考虑决定了实际使用的厚度，因此耐腐蚀性。需要一种以最小成本防止触点腐蚀并提供性能均匀的连接器的方法。作者成功地开发了一种镀后表面处理方法，该方法可以提供0.1 μ m厚的金接触面，足以防止24小时暴露在标准混合气体加速试验中。曝光后，0.1 μ m金在镍基板上的接触电阻低于50 m ω，而在哑光镍磷合金上的接触电阻低于5 m ω。
{"title":"Protective treatments for gold flashed finishes with a nickel substrate","authors":"N.H. Law, J. Sapjeta, E. S. Sproles","doi":"10.1109/HOLM.1991.170825","DOIUrl":"https://doi.org/10.1109/HOLM.1991.170825","url":null,"abstract":"While precious metals such as gold or gold flashed palladium are preferred contact materials for connectors, cost considerations dictate the actual thickness used and hence the corrosion resistance. A method of preventing corrosion on contacts and providing connectors with uniform performance at a minimal cost is desirable. The authors were successful in developing a post-plating surface treatment that provides 0.1- mu m-thick gold contact finishes sufficient protection against 24-hr exposure to a standard mixed gas accelerated test. After the exposure, the contact resistance of 0.1- mu m gold on a nickel substrate is below 50 m Omega , while the same over a matte-finish nickel phosphorus alloy is below 5 m Omega .<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134140427","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}
The effects of graphite particle size and sintered density on the contact performance of silver-5 wt.% graphite materials were evaluated. Materials made from larger graphite particles eroded more slowly but formed stronger welds relative to materials made using finer graphite particles. The slower erosion is due to the larger intergraphite particle spacing within the material, which allows the establishment of a more cohesive silver matrix. Due to the better silver interconnection, larger silver masses form on the contact surface, which causes the formation of strong welds. Higher sintered density reduced the erosion rate of the materials tested, with the greater effect being for the material with the finer graphite particles. The formation of carbon layers on the eroded contact surfaces was noted. A process by which carbon could be deposited from vapor species in the arc is described.<>
{"title":"The effects of graphite particle size and processing on the performance of silver-graphite contacts","authors":"P. Wingert, S. Allen, R. Bevington","doi":"10.1109/33.142888","DOIUrl":"https://doi.org/10.1109/33.142888","url":null,"abstract":"The effects of graphite particle size and sintered density on the contact performance of silver-5 wt.% graphite materials were evaluated. Materials made from larger graphite particles eroded more slowly but formed stronger welds relative to materials made using finer graphite particles. The slower erosion is due to the larger intergraphite particle spacing within the material, which allows the establishment of a more cohesive silver matrix. Due to the better silver interconnection, larger silver masses form on the contact surface, which causes the formation of strong welds. Higher sintered density reduced the erosion rate of the materials tested, with the greater effect being for the material with the finer graphite particles. The formation of carbon layers on the eroded contact surfaces was noted. A process by which carbon could be deposited from vapor species in the arc is described.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134525248","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}
For low-voltage circuit breakers, arc breaking by squeezing the arc in a narrow insulating slot is an interesting alternative to the conventional technique of using arc chutes with steel plates. The performance of a switching device based on this principle was experimentally investigated. The influence of slot dimension, switching speed, insulating material, and other test parameters on the arc breaking characteristics was determined. The results show that the arc voltage in the slot chambers depends mostly on the arc length (moving speed of the plate) and the cross-sectional area of the slot, while the influence of the insulating material and the shape of the slot plays only a minor role. By using a simplified ar model the curves of arc voltage and arc current can be simulated. There is a good agreement between the experimental and the calculated results.<>
{"title":"Current-limiting switching by squeezing arcs into narrow insulating slots","authors":"M. Lindmayer, Z. Huang","doi":"10.1109/33.142889","DOIUrl":"https://doi.org/10.1109/33.142889","url":null,"abstract":"For low-voltage circuit breakers, arc breaking by squeezing the arc in a narrow insulating slot is an interesting alternative to the conventional technique of using arc chutes with steel plates. The performance of a switching device based on this principle was experimentally investigated. The influence of slot dimension, switching speed, insulating material, and other test parameters on the arc breaking characteristics was determined. The results show that the arc voltage in the slot chambers depends mostly on the arc length (moving speed of the plate) and the cross-sectional area of the slot, while the influence of the insulating material and the shape of the slot plays only a minor role. By using a simplified ar model the curves of arc voltage and arc current can be simulated. There is a good agreement between the experimental and the calculated results.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133216383","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 : 1900-01-01DOI: 10.1109/holm.1991.170800
W. Rieder, V. Weichsler
The reason for the different make erosion behavior of contactor contacts made from Ag/CdO and Ag/SnO/sub 2/ has been investigated, separating the effects of the thermal stress due to the bounce arc from the mechanical stress due to contact closure. It appears that neither arcing without mechanical stress nor no-load switching without arcing is able to produce serious mass losses. Only the combined action of bounce arcs followed by mechanical impacts causes severe erosion phenomena, which are more pronounced in Ag/SnO/sub 2/ contacts, losing more obviously weakly adhering matter due to mechanical effects.<>
{"title":"Make erosion mechanism of Ag/CdO and Ag/SnO2 contacts","authors":"W. Rieder, V. Weichsler","doi":"10.1109/holm.1991.170800","DOIUrl":"https://doi.org/10.1109/holm.1991.170800","url":null,"abstract":"The reason for the different make erosion behavior of contactor contacts made from Ag/CdO and Ag/SnO/sub 2/ has been investigated, separating the effects of the thermal stress due to the bounce arc from the mechanical stress due to contact closure. It appears that neither arcing without mechanical stress nor no-load switching without arcing is able to produce serious mass losses. Only the combined action of bounce arcs followed by mechanical impacts causes severe erosion phenomena, which are more pronounced in Ag/SnO/sub 2/ contacts, losing more obviously weakly adhering matter due to mechanical effects.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"343 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128833651","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 : 1900-01-01DOI: 10.1109/HOLM.1991.170817
H. Haessler, M. Linde
The current leakage between the brushes and commutators of electrical motors generates arcs causing high-frequency pulses in the commutating current. Pulse amplitude and intensity depends on the material pairs, wear-in conditions, and mechanical tolerances of the brush-commutator system. To investigate the brush sparking of electric motors the high-frequency part of the motor current between 1 MKz and 50 MHz was considered. By use of a spectrum analyzer and advanced evaluation methods the quality of commutation can be determined. The high-frequency part of the motor current is an equivalent criterion of the intensity and arc rate of the brush sparking for quality assessment. The applicability of this method was tested using 25 AC motors rated at 230 V and 1.2 kW. In a first coarse evaluation of the measurement, good correlation between the new electronic and the conventional subjective-optical method was found. The information volume contained in the electrical spectrum, however, is considerably greater than that obtainable by the optical method.<>
{"title":"A new measurement technique for the investigation of arcing processes of sliding contacts","authors":"H. Haessler, M. Linde","doi":"10.1109/HOLM.1991.170817","DOIUrl":"https://doi.org/10.1109/HOLM.1991.170817","url":null,"abstract":"The current leakage between the brushes and commutators of electrical motors generates arcs causing high-frequency pulses in the commutating current. Pulse amplitude and intensity depends on the material pairs, wear-in conditions, and mechanical tolerances of the brush-commutator system. To investigate the brush sparking of electric motors the high-frequency part of the motor current between 1 MKz and 50 MHz was considered. By use of a spectrum analyzer and advanced evaluation methods the quality of commutation can be determined. The high-frequency part of the motor current is an equivalent criterion of the intensity and arc rate of the brush sparking for quality assessment. The applicability of this method was tested using 25 AC motors rated at 230 V and 1.2 kW. In a first coarse evaluation of the measurement, good correlation between the new electronic and the conventional subjective-optical method was found. The information volume contained in the electrical spectrum, however, is considerably greater than that obtainable by the optical method.<<ETX>>","PeriodicalId":368900,"journal":{"name":"Electrical Contacts - 1991 Proceedings of the Thirty-Seventh IEEE HOLM Conference on Electrical Contacts","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123203523","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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