Pub Date : 2016-10-09DOI: 10.1109/HOLM.2016.7780010
P. Chrétien, S. Noël, A. Jaffré, F. Houzé, D. Brunei, J. Njeim
Developing low friction and high conduction layers for electrical contacts has been a challenge for many years. Graphene is known to display outstanding friction and electrical behaviors; lately much work has been conducted both in the applied and fundamental fields of friction in order to understand the mechanisms involved. In the past years we have done experimental work on the tribological behavior of galvanic gold surfaces coated with various types of graphene-like coatings deposited by spraying liquid phase exfoliated graphite. The results showed that the unevenly distributed graphene-like flakes on the surface could bring strong friction reduction. However such coatings are difficult to control and a more controllable deposition technique such as CVD is considered here. The aim of this work is to start investigating the effect of friction on the properties of graphene layers at a microscopic scale and at a macroscopic scale. The first aspect is presented here. In order to assess the effect of friction and wear on graphene films, an atomic force microscope (AFM) is used. The effects of friction of the cantilever tip on the graphene coated plane are investigated. Topographic and electrical properties of the wear scars are recorded as well as the structure of the coating, thanks to a new customized system consisting of a Conducting Probe-AFM (CP-AFM) fitted confocal Raman microscope. Simultaneous topographic maps, electrical maps and Raman maps can be recorded on the friction tracks produced on the graphene coated surfaces. Electrical maps are built from the local values of tip/surface resistance while structure maps are built from the intensity of chosen representative peaks of the Raman spectra. Preliminary results were acquired on CVD graphene transferred to a silicon substrate. This involves a special technique that can induce defects in the graphene film and leave some insulating contamination on the surface. Friction behavior is investigated for different numbers of cycles and for different normal loads. Both parameters seem to govern the behavior of the graphene film. The quantity of defects in the film structure and its wear off are correlated. From the understanding of the mechanisms involved in controlled samples such as CVD graphene on silicon, we aim at bringing insight in the behavior of graphene coatings deposited on gold for an electrical contact application. Such knowledge is necessary to assess the durability of the coatings in various situations such as wear and atmospheric ageing.
{"title":"Electrical and structural mapping of friction induced defects in graphene layers","authors":"P. Chrétien, S. Noël, A. Jaffré, F. Houzé, D. Brunei, J. Njeim","doi":"10.1109/HOLM.2016.7780010","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780010","url":null,"abstract":"Developing low friction and high conduction layers for electrical contacts has been a challenge for many years. Graphene is known to display outstanding friction and electrical behaviors; lately much work has been conducted both in the applied and fundamental fields of friction in order to understand the mechanisms involved. In the past years we have done experimental work on the tribological behavior of galvanic gold surfaces coated with various types of graphene-like coatings deposited by spraying liquid phase exfoliated graphite. The results showed that the unevenly distributed graphene-like flakes on the surface could bring strong friction reduction. However such coatings are difficult to control and a more controllable deposition technique such as CVD is considered here. The aim of this work is to start investigating the effect of friction on the properties of graphene layers at a microscopic scale and at a macroscopic scale. The first aspect is presented here. In order to assess the effect of friction and wear on graphene films, an atomic force microscope (AFM) is used. The effects of friction of the cantilever tip on the graphene coated plane are investigated. Topographic and electrical properties of the wear scars are recorded as well as the structure of the coating, thanks to a new customized system consisting of a Conducting Probe-AFM (CP-AFM) fitted confocal Raman microscope. Simultaneous topographic maps, electrical maps and Raman maps can be recorded on the friction tracks produced on the graphene coated surfaces. Electrical maps are built from the local values of tip/surface resistance while structure maps are built from the intensity of chosen representative peaks of the Raman spectra. Preliminary results were acquired on CVD graphene transferred to a silicon substrate. This involves a special technique that can induce defects in the graphene film and leave some insulating contamination on the surface. Friction behavior is investigated for different numbers of cycles and for different normal loads. Both parameters seem to govern the behavior of the graphene film. The quantity of defects in the film structure and its wear off are correlated. From the understanding of the mechanisms involved in controlled samples such as CVD graphene on silicon, we aim at bringing insight in the behavior of graphene coatings deposited on gold for an electrical contact application. Such knowledge is necessary to assess the durability of the coatings in various situations such as wear and atmospheric ageing.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"168 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114347330","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.2016.7780033
E. K. Snipes, G. Flowers, M. Bozack
Large variations in the coefficient of thermal expansion (CTE) between Sn and growth substrates provide a highly reliable and fast method to grow whiskers. The CTE effect can be enhanced by thermal cycling during whisker incubation, which is able to reverse reductions in whiskering due to small amounts of dopant atoms in the Sn (e.g., Pb). Investigated substrates with CTE close in value to Sn (0 < %ΔCTE < 25) were Al, Ag, and brass; intermediate in value to Sn (25 < %ΔCTE < 75) were Zn, Ni, and Ta; and far in value to Sn (75 < %ΔCTE < 100) were semiconductors Si, GaAs, and InP. A thickness of 0.5 micron of sputtered Sn was deposited on each coupon. The thermal cycling range was −40°C to 125°C, with 2 hour ramps and 4 hour dwells, for a total of 12 hours per cycle. A second, comparative set of specimens underwent isothermal annealing at 100°C ± 5°C. All samples were incubated for 37 days (74 cycles) before observation. Samples with a %ΔCTE > 75% resulted in drastically higher whisker densities (when cycled) compared with those with %ΔCTE < 75%. There appears to be a critical activation (or nucleation) threshold CTE mismatch which “turns on” fast whisker growth when using semiconductors as substrates.
{"title":"Influence of systematic coefficient of thermal expansion (CTE) variations on Sn whiskering","authors":"E. K. Snipes, G. Flowers, M. Bozack","doi":"10.1109/HOLM.2016.7780033","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780033","url":null,"abstract":"Large variations in the coefficient of thermal expansion (CTE) between Sn and growth substrates provide a highly reliable and fast method to grow whiskers. The CTE effect can be enhanced by thermal cycling during whisker incubation, which is able to reverse reductions in whiskering due to small amounts of dopant atoms in the Sn (e.g., Pb). Investigated substrates with CTE close in value to Sn (0 < %ΔCTE < 25) were Al, Ag, and brass; intermediate in value to Sn (25 < %ΔCTE < 75) were Zn, Ni, and Ta; and far in value to Sn (75 < %ΔCTE < 100) were semiconductors Si, GaAs, and InP. A thickness of 0.5 micron of sputtered Sn was deposited on each coupon. The thermal cycling range was −40°C to 125°C, with 2 hour ramps and 4 hour dwells, for a total of 12 hours per cycle. A second, comparative set of specimens underwent isothermal annealing at 100°C ± 5°C. All samples were incubated for 37 days (74 cycles) before observation. Samples with a %ΔCTE > 75% resulted in drastically higher whisker densities (when cycled) compared with those with %ΔCTE < 75%. There appears to be a critical activation (or nucleation) threshold CTE mismatch which “turns on” fast whisker growth when using semiconductors as substrates.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"35 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":"116950346","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.2016.7780004
J. Mannekutla, R. Bianchetti, Andreas Friberg, T. Delachaux, P. Sutterlin
Ablation from polymeric casing materials has a pivotal role in switching devices. The ablated gases influence the arc properties and assist the arc movement during current interruption. In this study, spatially resolved optical emission spectroscopy is used to determine the temperature distribution across a switching arc. A simplified setup is built to mimic the conditions found in low voltage switching devices. The quantification of the temperature variations due to the interactions between an arc and ablated vapors from the polymeric walls are aimed in this work. As a marker for temperature, atomic and ionic lines of copper are used. The copper spectral radiance is simulated using ad-hoc temperature profiles. The temperature profiles used to simulate the spectra are adapted until the simulated spectra match with the ones obtained experimentally. This method works well in the copper dominated core region of the arcs. In proximity of polymeric walls, it is of limited use due to the low temperatures and concentration of copper. In addition, C2 molecular emission close to the walls overlaps with the copper lines. The inferred temperatures are then employed to assess the cooling effect of different polymeric materials in function of current and geometry.
{"title":"Temperature distribution in ablation controlled switching arcs using optical emission spectroscopy","authors":"J. Mannekutla, R. Bianchetti, Andreas Friberg, T. Delachaux, P. Sutterlin","doi":"10.1109/HOLM.2016.7780004","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780004","url":null,"abstract":"Ablation from polymeric casing materials has a pivotal role in switching devices. The ablated gases influence the arc properties and assist the arc movement during current interruption. In this study, spatially resolved optical emission spectroscopy is used to determine the temperature distribution across a switching arc. A simplified setup is built to mimic the conditions found in low voltage switching devices. The quantification of the temperature variations due to the interactions between an arc and ablated vapors from the polymeric walls are aimed in this work. As a marker for temperature, atomic and ionic lines of copper are used. The copper spectral radiance is simulated using ad-hoc temperature profiles. The temperature profiles used to simulate the spectra are adapted until the simulated spectra match with the ones obtained experimentally. This method works well in the copper dominated core region of the arcs. In proximity of polymeric walls, it is of limited use due to the low temperatures and concentration of copper. In addition, C2 molecular emission close to the walls overlaps with the copper lines. The inferred temperatures are then employed to assess the cooling effect of different polymeric materials in function of current and geometry.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"253 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":"122079799","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.2016.7780037
Jens Jebramcik, F. Berger
Contrary to other test setups, a virtually unmodified contactor actuator has been integrated into a model switch to reproduce contact bouncing of make operations. This allows for a less complex machine than an electro mechanical or pneumatic replica of the original actuator. Furthermore optical and mechanical access to the contacts is significantly improved compared to a standard contactor. Scattered failure of the contact system has been traced down to contact welding during make operations instead of welding by over-currents in the on-state. Investigations of the welded contact have been rather limited without completely destroying the contactor housing for extraction. The model setup facilitates series switching with recording of electrical parameters as well as contact closing and separation forces and contact bridge displacement. Welded contacts can be teared open by an additional actuator to detect welding forces in place or can be simply disassembled for further analysis without damaging the weld spot. The authors present first results from their test sequences and reveal the significance of pre-impact arcing for the total energy dissipation in make operations.
{"title":"Investigations on the make-welding behavior of high power contactors for AC and DC applications up to 3kV","authors":"Jens Jebramcik, F. Berger","doi":"10.1109/HOLM.2016.7780037","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780037","url":null,"abstract":"Contrary to other test setups, a virtually unmodified contactor actuator has been integrated into a model switch to reproduce contact bouncing of make operations. This allows for a less complex machine than an electro mechanical or pneumatic replica of the original actuator. Furthermore optical and mechanical access to the contacts is significantly improved compared to a standard contactor. Scattered failure of the contact system has been traced down to contact welding during make operations instead of welding by over-currents in the on-state. Investigations of the welded contact have been rather limited without completely destroying the contactor housing for extraction. The model setup facilitates series switching with recording of electrical parameters as well as contact closing and separation forces and contact bridge displacement. Welded contacts can be teared open by an additional actuator to detect welding forces in place or can be simply disassembled for further analysis without damaging the weld spot. The authors present first results from their test sequences and reveal the significance of pre-impact arcing for the total energy dissipation in make operations.","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":"129061761","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.2016.7780035
Kiyoshi Yoshida, Shu Shimotsuma, K. Sawa, Kenji Suzuki, K. Takaya
Experiments are carried out to clarify the influence on the current and voltage for various characteristics. A small electromagnetic contactor that has two contacts is used. The arc discharge with only a make arc is generated and various characteristics are measured. Source voltage is set to 100V or 3V DC, closed contacts currents are changed from 10A 20A and 30A. From the waveforms, the arc duration time and the bounce time are read out. Arc energy is calculated from the arc voltage and arc current. The contact resistance is calculated from the voltage drops. In DC100V, the arc duration time and the bounce time were not influenced by a closed contact current. The arc energy was increased by a closed contact current. The contact resistance was slightly decreased with current increases. The mass change of electrodes, the anode was decreased and the cathode was increased. Further the electrode mass change per unit arc energy vs. closed current was relatively constant. But, in DC3V make arc duration is very short and electrode mass change is very small.
{"title":"Various characteristics of electromagnetic contactor when arc discharge are generated only make arc","authors":"Kiyoshi Yoshida, Shu Shimotsuma, K. Sawa, Kenji Suzuki, K. Takaya","doi":"10.1109/HOLM.2016.7780035","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780035","url":null,"abstract":"Experiments are carried out to clarify the influence on the current and voltage for various characteristics. A small electromagnetic contactor that has two contacts is used. The arc discharge with only a make arc is generated and various characteristics are measured. Source voltage is set to 100V or 3V DC, closed contacts currents are changed from 10A 20A and 30A. From the waveforms, the arc duration time and the bounce time are read out. Arc energy is calculated from the arc voltage and arc current. The contact resistance is calculated from the voltage drops. In DC100V, the arc duration time and the bounce time were not influenced by a closed contact current. The arc energy was increased by a closed contact current. The contact resistance was slightly decreased with current increases. The mass change of electrodes, the anode was decreased and the cathode was increased. Further the electrode mass change per unit arc energy vs. closed current was relatively constant. But, in DC3V make arc duration is very short and electrode mass change is very small.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"4 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":"122264301","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.2016.7780028
Le Xu, S. Ling, Rao Fu, G. Zhai
RF (Radio Frequency) coaxial switches have the advantages of high transmission frequency and high power capacity, and are widely used in aerospace, communications, military, science and medical fields. In this paper, a three-dimensional finite element model of a RF coaxial switch was first proposed. The power loss in the contact system when the switch transmits high frequency and power signals was divided into the conductor loss and the dielectric loss which were calculated separately. It was noted that conductor loss was the main part of power loss. Then, the power loss in the contact system was considered as the heat source and the steady state temperature field of the whole switch was calculated with Ansoft HFSS and Workbench. The temperature rise in a RF coaxial switch was calculated and verified by experimental testing. Finally, the influence of transmission power was examined and it was concluded that the RF performance would downgrade with increasing transmission power and steady state temperature because of the thermal deformation occurring in the contact system caused by the heat stress. The analysis methods and conclusions presented in this study have important theoretical significance and practical value for improving the performance and reliability of RF coaxial switch products.
{"title":"Study on thermal characteristics of RF coaxial switch based on finite element method","authors":"Le Xu, S. Ling, Rao Fu, G. Zhai","doi":"10.1109/HOLM.2016.7780028","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780028","url":null,"abstract":"RF (Radio Frequency) coaxial switches have the advantages of high transmission frequency and high power capacity, and are widely used in aerospace, communications, military, science and medical fields. In this paper, a three-dimensional finite element model of a RF coaxial switch was first proposed. The power loss in the contact system when the switch transmits high frequency and power signals was divided into the conductor loss and the dielectric loss which were calculated separately. It was noted that conductor loss was the main part of power loss. Then, the power loss in the contact system was considered as the heat source and the steady state temperature field of the whole switch was calculated with Ansoft HFSS and Workbench. The temperature rise in a RF coaxial switch was calculated and verified by experimental testing. Finally, the influence of transmission power was examined and it was concluded that the RF performance would downgrade with increasing transmission power and steady state temperature because of the thermal deformation occurring in the contact system caused by the heat stress. The analysis methods and conclusions presented in this study have important theoretical significance and practical value for improving the performance and reliability of RF coaxial switch products.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"828 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":"133280070","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.2016.7780005
K. Yasuoka, Tsuboi Yoshiki, Tatsuya Hayakawa, Tamanosuke Oide, N. Takeuchi
DC circuit breakers (DCCBs) have been intensively studied because of increasing demand for DC power transmission. A hybrid DC circuit breaker that consists of mechanical switches, semiconductor devices, and metal-oxide varistor (MOV) elements is a promising device to provide low contact resistance and a fast interruption. The semiconductor devices are turned on by the sustaining voltage of arc discharge generated between the metal contacts of the mechanical switch. Though arc duration time in the hybrid DCCB is shorter than that in classical mechanical CBs, the arc causes contact erosion. In this report, an arcless commutation is described that uses the molten metal-bridge voltage at the opening stage of the contacts. The magnitude of the molten-bridge voltage is just enough to turn on SiC-MOSFET devices under specific conditions. Arcless commutation of DC current was observed with a Ag-W vacuum contact and SiC-MOSFETs at current values of 78∼140 A.
{"title":"A hybrid DC circuit breaker with vacuum contact and SiC-MOSFET for arcless commutation","authors":"K. Yasuoka, Tsuboi Yoshiki, Tatsuya Hayakawa, Tamanosuke Oide, N. Takeuchi","doi":"10.1109/HOLM.2016.7780005","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780005","url":null,"abstract":"DC circuit breakers (DCCBs) have been intensively studied because of increasing demand for DC power transmission. A hybrid DC circuit breaker that consists of mechanical switches, semiconductor devices, and metal-oxide varistor (MOV) elements is a promising device to provide low contact resistance and a fast interruption. The semiconductor devices are turned on by the sustaining voltage of arc discharge generated between the metal contacts of the mechanical switch. Though arc duration time in the hybrid DCCB is shorter than that in classical mechanical CBs, the arc causes contact erosion. In this report, an arcless commutation is described that uses the molten metal-bridge voltage at the opening stage of the contacts. The magnitude of the molten-bridge voltage is just enough to turn on SiC-MOSFET devices under specific conditions. Arcless commutation of DC current was observed with a Ag-W vacuum contact and SiC-MOSFETs at current values of 78∼140 A.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"5 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":"133625576","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.2016.7780020
D. Gonzalez, F. Berger, M. Hopfeld, P. Schaaf
As a first step in a long-term planned cooperation between the TU Ilmenau and several industry partners a model switch was developed and constructed in order to investigate the influence of different aspects affecting the evolution of contact resistance during the lifetime of electrical contacts in low voltage contactors. The device permits, besides the variation of different geometrical and kinetic parameters, the determination of the contact resistance by different contact closing forces. Several material analysis methods, such as laser surface profilometry, light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were applied to Ag/Ni10 contacts before and after experimental series with breaking AC-arcs according to IEC 60947. Important information regarding surface structure, chemical composition and formed crystalline phases of the surface contact materials and ambient materials were obtained. The main characteristics of the model switch and some results of the first experiments are presented in this paper.
{"title":"Model switch experiments for determining the evolution of contact resistance of electrical contacts in contactors","authors":"D. Gonzalez, F. Berger, M. Hopfeld, P. Schaaf","doi":"10.1109/HOLM.2016.7780020","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780020","url":null,"abstract":"As a first step in a long-term planned cooperation between the TU Ilmenau and several industry partners a model switch was developed and constructed in order to investigate the influence of different aspects affecting the evolution of contact resistance during the lifetime of electrical contacts in low voltage contactors. The device permits, besides the variation of different geometrical and kinetic parameters, the determination of the contact resistance by different contact closing forces. Several material analysis methods, such as laser surface profilometry, light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were applied to Ag/Ni10 contacts before and after experimental series with breaking AC-arcs according to IEC 60947. Important information regarding surface structure, chemical composition and formed crystalline phases of the surface contact materials and ambient materials were obtained. The main characteristics of the model switch and some results of the first experiments are presented in this paper.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"35 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":"133209747","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.2016.7780024
Haoyue Yang, Y. Tong, G. Flowers, Zhongyang Cheng
Fretting degradation is generally recognized as one of the major failure mechanisms for electrical connector systems. The major driver of fretting damage is relative motion at the contact interface, producing material displacement and transfer. For non-precious metal plated contact interfaces, this fretting damage serves to repeatedly expose fresh metal to atmospheric oxidation. The result is a substantial and rapid increase in contact resistance due to a localized buildup of an insulating layer. Relative motion at the contact interface can be induced by thermal expansion/contraction, vibration, or by a combination of the two mechanisms. There has been considerable recent work on this topic, including experimental investigations and model development work. Much of this previous work on fretting degradation has focused on the increase in electrical resistance resulting from the buildup of corrosion products (the insulating layer) in the interface between the blade and the receptacle. However, the physical separation of the blade and receptacle by the corrosion products also produces a capacitance effect that has not been previously explored in detail. The present study seeks to explore this phenomenon and develop an understanding of its significance. An experimental study was performed to investigate the fashion of the capacitance build-up subjected to vibration induced fretting motion. A simple model is also developed which relates the capacitance behavior to connector characteristic, vibration profile and resistance behavior. A series of experiments and simulation studies have been performed to explore the physical behavior of such systems and study the capacitance effects of the insulating layer. Of particular interest is the effect on signal phase and frequency response across the connector interface and how these effects might be employed to monitor the health of connector systems used for communication signals.
{"title":"Capacitance build-up in electrical connectors due to vibration induce fretting corrosion","authors":"Haoyue Yang, Y. Tong, G. Flowers, Zhongyang Cheng","doi":"10.1109/HOLM.2016.7780024","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780024","url":null,"abstract":"Fretting degradation is generally recognized as one of the major failure mechanisms for electrical connector systems. The major driver of fretting damage is relative motion at the contact interface, producing material displacement and transfer. For non-precious metal plated contact interfaces, this fretting damage serves to repeatedly expose fresh metal to atmospheric oxidation. The result is a substantial and rapid increase in contact resistance due to a localized buildup of an insulating layer. Relative motion at the contact interface can be induced by thermal expansion/contraction, vibration, or by a combination of the two mechanisms. There has been considerable recent work on this topic, including experimental investigations and model development work. Much of this previous work on fretting degradation has focused on the increase in electrical resistance resulting from the buildup of corrosion products (the insulating layer) in the interface between the blade and the receptacle. However, the physical separation of the blade and receptacle by the corrosion products also produces a capacitance effect that has not been previously explored in detail. The present study seeks to explore this phenomenon and develop an understanding of its significance. An experimental study was performed to investigate the fashion of the capacitance build-up subjected to vibration induced fretting motion. A simple model is also developed which relates the capacitance behavior to connector characteristic, vibration profile and resistance behavior. A series of experiments and simulation studies have been performed to explore the physical behavior of such systems and study the capacitance effects of the insulating layer. Of particular interest is the effect on signal phase and frequency response across the connector interface and how these effects might be employed to monitor the health of connector systems used for communication signals.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"91 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":"127660189","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.2016.7780008
T. Yudate, J. Toyoizumi, M. Onuma, T. Kondo, T. Shimizu, S. Kawabata, N. Watanabe, K. Mori
Electrical connectors plated with tin are widely used in automobiles. Therefore, it is important to understand electrical conduction mechanism and contact structure of tin plating which is coated with thin oxide layer in order to realize small electrical connectors which are able to operate under low load force condition. Then we constructed nano-manipulator to be able to observe the mechanical contact, measure the load force and electrical resistance simultaneously in a scanning electron microscope. As a result, we found that the electrical resistance drastically reduces as the load force increases, and could observe that the tin penetrates into cracks in oxide layer and finally reaches on the surface. These results are the same as those of tin oxide layer fabricated by sputtering. Therefore, it is confirmed that the tin appearance on the contact surface is very important for electrical conduction even in the case of tin with natural oxide. For size miniaturization and load force reduction of tin plating connectors in near future, it is necessary to focus on the oxide layer fracturing and control the tin appearance on the contact interface.
{"title":"The investigation of the electrical contact resistance through thin oxide layer on a nanometer scale","authors":"T. Yudate, J. Toyoizumi, M. Onuma, T. Kondo, T. Shimizu, S. Kawabata, N. Watanabe, K. Mori","doi":"10.1109/HOLM.2016.7780008","DOIUrl":"https://doi.org/10.1109/HOLM.2016.7780008","url":null,"abstract":"Electrical connectors plated with tin are widely used in automobiles. Therefore, it is important to understand electrical conduction mechanism and contact structure of tin plating which is coated with thin oxide layer in order to realize small electrical connectors which are able to operate under low load force condition. Then we constructed nano-manipulator to be able to observe the mechanical contact, measure the load force and electrical resistance simultaneously in a scanning electron microscope. As a result, we found that the electrical resistance drastically reduces as the load force increases, and could observe that the tin penetrates into cracks in oxide layer and finally reaches on the surface. These results are the same as those of tin oxide layer fabricated by sputtering. Therefore, it is confirmed that the tin appearance on the contact surface is very important for electrical conduction even in the case of tin with natural oxide. For size miniaturization and load force reduction of tin plating connectors in near future, it is necessary to focus on the oxide layer fracturing and control the tin appearance on the contact interface.","PeriodicalId":117231,"journal":{"name":"2016 IEEE 62nd Holm Conference on Electrical Contacts (Holm)","volume":"28 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":"115580674","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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