Pub Date : 2020-09-30DOI: 10.1109/HLM49214.2020.9307870
Zhe Zheng, Tianyang Wang, Xu Zhang, W. Ren
The contact welding failure of general-purposed relay closely relates to alternating current (AC) arc erosion. In this paper, AC arc behavior is investigated by a general-purpose relay firstly. The typical waveforms of arc voltage and current during contact making and breaking are presented, then the effects of point-on-wave (POW) at break on arc energy is analyzed explicitly. Based on the degradation processes of contact opening time and making heat occurred in the electrical endurance experiment, the possible physical mechanism of contact welding failure for general-purposed relay is proposed.
{"title":"Experimental Investigation of Alternating Current Arc Behavior and Associated Contact Welding Failure for General-purpose Relay","authors":"Zhe Zheng, Tianyang Wang, Xu Zhang, W. Ren","doi":"10.1109/HLM49214.2020.9307870","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307870","url":null,"abstract":"The contact welding failure of general-purposed relay closely relates to alternating current (AC) arc erosion. In this paper, AC arc behavior is investigated by a general-purpose relay firstly. The typical waveforms of arc voltage and current during contact making and breaking are presented, then the effects of point-on-wave (POW) at break on arc energy is analyzed explicitly. Based on the degradation processes of contact opening time and making heat occurred in the electrical endurance experiment, the possible physical mechanism of contact welding failure for general-purposed relay is proposed.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114862090","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307840
L. Claassen, Frederik Anspach, Ernst-Dieter Wilkening, M. Kurrat
Transmission and distribution of electrical energy has been achieved by using alternating current (AC) almost exclusively until now. Direct current (DC) pushes forward into long range energy transmission, server farms, mobility and manufacturing systems, being former AC dominated areas. With potential advantages of DC there are also different challenges like switching nominal and fault currents and ensuring that only affected parts of DC grids are disabled when failures occur.The government-funded research project Smart Modular Switchgear (SMS I) resulted in the proposal of a novel, algorithm-based low voltage DC protection system, facing those challenges. Fast, selective and reliable switching operations were achieved even with multiple distributed power supplies included in one power grid. Former results of these studies indicate that a hybrid circuit breaker (HCB) is the most suitable switch for this application. In this contribution the mechanical component of a model HCB is investigated by measuring and evaluating the on-state resistance and the interruption behavior under different load conditions and with two different contact materials. Furthermore, these results are compared to other direct current switches (DCS). Finally, the usability of the switch is discussed for the project SMS II where higher voltage levels are subject of the research focus.
{"title":"Investigation of a Mechanical Switch within a Hybrid Circuit Breaker for Protection in DC Grids","authors":"L. Claassen, Frederik Anspach, Ernst-Dieter Wilkening, M. Kurrat","doi":"10.1109/HLM49214.2020.9307840","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307840","url":null,"abstract":"Transmission and distribution of electrical energy has been achieved by using alternating current (AC) almost exclusively until now. Direct current (DC) pushes forward into long range energy transmission, server farms, mobility and manufacturing systems, being former AC dominated areas. With potential advantages of DC there are also different challenges like switching nominal and fault currents and ensuring that only affected parts of DC grids are disabled when failures occur.The government-funded research project Smart Modular Switchgear (SMS I) resulted in the proposal of a novel, algorithm-based low voltage DC protection system, facing those challenges. Fast, selective and reliable switching operations were achieved even with multiple distributed power supplies included in one power grid. Former results of these studies indicate that a hybrid circuit breaker (HCB) is the most suitable switch for this application. In this contribution the mechanical component of a model HCB is investigated by measuring and evaluating the on-state resistance and the interruption behavior under different load conditions and with two different contact materials. Furthermore, these results are compared to other direct current switches (DCS). Finally, the usability of the switch is discussed for the project SMS II where higher voltage levels are subject of the research focus.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125822994","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307860
Zekun Wang, G. Flowers, M. Bozack
An important question in Sn whisker research concerns the role of lateral Sn diffusion in the film to the whisker root, providing the feedstock for whisker growth. In an elegant tracer experiment on diffusion in Sn films, Woodrow (2006) observed lateral atomic Sn diffusion over distances of hundreds and thousands of microns through Sn grain boundaries during whisker growth. In this work, we examine the effect of limiting the lateral extent of the Sn feedstock available during whiskering by employing extremely thin, micron-sized patterned Sn deposits, and compare to whisker growth from an comparatively large, essentially infinite (1cm x 1cm) thin Sn film. A series of metal, mesh grids of varying sizes were used as masks to define the area of sputtered tin deposited on Si substrates. The defined areas were primarily in the form of squares, with sizes ranging from7.5µm x 7.5µm to 153µm x 153µm. Sample areas also included 2 circles, with radii of 1µm and 4µm, and a rectangular strip with dimensions 46µm x 3000µm. A thickness of ~500Å of sputtered Sn was deposited on each specimen. The samples were subsequently incubated for 34 days under three incubation conditions: 23oC (isothermal); 100oC (isothermal); and thermal cycling over -40oCoC. Characteristically, higher whisker densities were observed as the patterned Sn area size increased, e.g., the 153µm patterns had ~ 3X more whiskers compared to the 23µm patterns under the same incubation conditions. There was a discontinuous transition in whisker density at the smallest patterned area sizes, with few whiskers found on the 7.5µm-23µm dimensioned square patterns and no whiskers found on the 1µm and 4µm patterns. Further, the whiskers obtained from micron-size areas of sputtered Sn are predominantly hillock in nature, in contrast to the high-aspect ratio whiskers normally grown from sputtered Sn on Si using standard sized films (1cm2) under identical growth conditions.
锡晶须研究中的一个重要问题是锡在薄膜中向晶须根部横向扩散的作用，为晶须生长提供原料。Woodrow(2006)在一个关于锡薄膜扩散的优雅示踪实验中，观察到在晶须生长过程中，锡原子沿锡晶界横向扩散了数百微米和数千微米的距离。在这项工作中，我们通过使用极薄的、微米级的图案锡沉积，研究了在晶须生成过程中限制锡原料横向范围的影响，并与相对较大的、基本上无限的(1cm x 1cm)锡薄膜的晶须生长进行了比较。一系列不同尺寸的金属网格被用作掩模来定义沉积在Si衬底上的溅射锡的区域。定义的区域主要是正方形的形式，尺寸范围从7.5微米x 7.5微米到153微米x 153微米。样本区域还包括2个半径为1微米和4微米的圆圈，以及一个尺寸为46微米x 3000微米的矩形带。在每个试样上沉积了~500Å厚度的溅射锡。样品随后在三种孵育条件下孵育34天:23℃(等温);100 oc(等温);在-40摄氏度的温度下进行热循环。随着图案Sn面积的增大，晶须密度增加，例如，在相同的孵育条件下，153µm图案的晶须比23µm图案的晶须多约3倍。在最小的图案面积上，晶须密度发生了不连续的转变，在7.5µm-23µm尺寸的正方形图案上几乎没有发现晶须，而在1µm和4µm尺寸的图案上没有发现晶须。此外，从微米大小的溅射锡区获得的晶须主要是丘陵性质的，与在相同生长条件下使用标准尺寸的薄膜(1cm2)在Si上溅射锡通常生长的高纵横比晶须形成对比。
{"title":"The Influence of Limitation of Sputtered Tin Area Through Mesh Grids on Sn Whiskering","authors":"Zekun Wang, G. Flowers, M. Bozack","doi":"10.1109/HLM49214.2020.9307860","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307860","url":null,"abstract":"An important question in Sn whisker research concerns the role of lateral Sn diffusion in the film to the whisker root, providing the feedstock for whisker growth. In an elegant tracer experiment on diffusion in Sn films, Woodrow (2006) observed lateral atomic Sn diffusion over distances of hundreds and thousands of microns through Sn grain boundaries during whisker growth. In this work, we examine the effect of limiting the lateral extent of the Sn feedstock available during whiskering by employing extremely thin, micron-sized patterned Sn deposits, and compare to whisker growth from an comparatively large, essentially infinite (1cm x 1cm) thin Sn film. A series of metal, mesh grids of varying sizes were used as masks to define the area of sputtered tin deposited on Si substrates. The defined areas were primarily in the form of squares, with sizes ranging from7.5µm x 7.5µm to 153µm x 153µm. Sample areas also included 2 circles, with radii of 1µm and 4µm, and a rectangular strip with dimensions 46µm x 3000µm. A thickness of ~500Å of sputtered Sn was deposited on each specimen. The samples were subsequently incubated for 34 days under three incubation conditions: 23oC (isothermal); 100oC (isothermal); and thermal cycling over -40oCoC. Characteristically, higher whisker densities were observed as the patterned Sn area size increased, e.g., the 153µm patterns had ~ 3X more whiskers compared to the 23µm patterns under the same incubation conditions. There was a discontinuous transition in whisker density at the smallest patterned area sizes, with few whiskers found on the 7.5µm-23µm dimensioned square patterns and no whiskers found on the 1µm and 4µm patterns. Further, the whiskers obtained from micron-size areas of sputtered Sn are predominantly hillock in nature, in contrast to the high-aspect ratio whiskers normally grown from sputtered Sn on Si using standard sized films (1cm2) under identical growth conditions.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130273851","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307846
Xin Zhou, Yanjun Feng, Z. Shen, S. Krstic
The demand for DC circuit protection products continues to grow as industry sectors such as electrical vehicles, energy storage and data centers further expand. It drives the need for cost effective and compact DC circuit protection devices with higher short circuit interruption ratings. This paper presents a novel hybrid DC molded case circuit breaker (MCCB) technology that enables single-pole 10kA/600VDC interruption capability. The design is based on existing MCCB switching mechanism and contact structure. It incorporates a galvanic isolation disconnect without adding Watt loss to the device when it is switched on. Unlike conventional hybrid breaker topologies that try to commutate the fault current as quickly as possible from the electromechanical path to the power electronic path, this hybrid MCCB topology utilizes the arc to absorb most of the inductance energy stored in a DC electrical system and to limit the fault current to a lower level before the commutation. Concept prototypes have been developed and investigated via both numerical simulation and experimentation. Test results show that this technology enables the DC single-pole MCCB to be able to not only interrupt 10kA/600VDC fault current, but also maintain the thermal performance of a conventional MCCB.
{"title":"Hybrid DC Molded Case Circuit Breaker Technology","authors":"Xin Zhou, Yanjun Feng, Z. Shen, S. Krstic","doi":"10.1109/HLM49214.2020.9307846","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307846","url":null,"abstract":"The demand for DC circuit protection products continues to grow as industry sectors such as electrical vehicles, energy storage and data centers further expand. It drives the need for cost effective and compact DC circuit protection devices with higher short circuit interruption ratings. This paper presents a novel hybrid DC molded case circuit breaker (MCCB) technology that enables single-pole 10kA/600VDC interruption capability. The design is based on existing MCCB switching mechanism and contact structure. It incorporates a galvanic isolation disconnect without adding Watt loss to the device when it is switched on. Unlike conventional hybrid breaker topologies that try to commutate the fault current as quickly as possible from the electromechanical path to the power electronic path, this hybrid MCCB topology utilizes the arc to absorb most of the inductance energy stored in a DC electrical system and to limit the fault current to a lower level before the commutation. Concept prototypes have been developed and investigated via both numerical simulation and experimentation. Test results show that this technology enables the DC single-pole MCCB to be able to not only interrupt 10kA/600VDC fault current, but also maintain the thermal performance of a conventional MCCB.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121416680","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307904
T. Damle, Chunmeng Xu, M. Varenberg, L. Graber
Fast Mechanical Switches (FMS) are a key component of energy-efficient hybrid circuit breakers for DC applications. Wear of the FMS impacts the performance and life expectancy of the breaker. The surface damage caused by fretting motion can alter the contact surfaces and reduce the voltage withstand capability of the FMS, especially in those that operate at sub-millimeter contact separation. This paper investigates the issue by conducting fretting experiments on copper contacts as a function of current magnitude to obtain surface parameters of the damaged contacts. Random surfaces based on the measured surface parameters are generated in a finite element software package. The electric field between the generated surfaces is obtained using electrostatic field modeling to calculate the probability of electric breakdown in the contact gap. The results are used to understand the potential impact of fretting on the breakdown voltage of FMS.
{"title":"Electric Field Between Contacts of Fast Mechanical Switches Subjected to Fretting Wear","authors":"T. Damle, Chunmeng Xu, M. Varenberg, L. Graber","doi":"10.1109/HLM49214.2020.9307904","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307904","url":null,"abstract":"Fast Mechanical Switches (FMS) are a key component of energy-efficient hybrid circuit breakers for DC applications. Wear of the FMS impacts the performance and life expectancy of the breaker. The surface damage caused by fretting motion can alter the contact surfaces and reduce the voltage withstand capability of the FMS, especially in those that operate at sub-millimeter contact separation. This paper investigates the issue by conducting fretting experiments on copper contacts as a function of current magnitude to obtain surface parameters of the damaged contacts. Random surfaces based on the measured surface parameters are generated in a finite element software package. The electric field between the generated surfaces is obtained using electrostatic field modeling to calculate the probability of electric breakdown in the contact gap. The results are used to understand the potential impact of fretting on the breakdown voltage of FMS.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128139538","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307900
Silei Chen, Yu Meng, Jing Wang, Xingwen Li
For intensely burning photovoltaic (PV) series arc faults without strong noise interferences, their time-frequency features are easily to be discovered. However, various PV systems would generate noise interferences to the arc fault signal, causing difficulties to distinguish the arc fault and normal states. To solve this kind of problem, new measurements should be taken to acquire obvious arc fault features even from the weak arc fault electrical signals.In this paper, weak PV series arc fault electrical signals are acquired from the designed experimental setup with different load types firstly. Then it is found that the performance of arc fault features are not that satisfying in higher frequency bands after directly applying the existing Db9 based wavelet transform, causing the arc fault detection problem. Next, arc fault features are enhanced in most frequency bands by conducting the proposed Rbio3.1 based wavelet transform. Finally, the stochastic resonance (SR) method is proposed to further enhance Rbio3.1-based arc fault feature. The compared results prove that the combination between SR method and Rbio3.1 wavelet transform show the effective feature enhancement ability facing weak PV series arc fault electrical signals with different inverters and resistors.
{"title":"Feature Enhancement Method for Weak Photovoltaic Series Arc Fault Signals","authors":"Silei Chen, Yu Meng, Jing Wang, Xingwen Li","doi":"10.1109/HLM49214.2020.9307900","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307900","url":null,"abstract":"For intensely burning photovoltaic (PV) series arc faults without strong noise interferences, their time-frequency features are easily to be discovered. However, various PV systems would generate noise interferences to the arc fault signal, causing difficulties to distinguish the arc fault and normal states. To solve this kind of problem, new measurements should be taken to acquire obvious arc fault features even from the weak arc fault electrical signals.In this paper, weak PV series arc fault electrical signals are acquired from the designed experimental setup with different load types firstly. Then it is found that the performance of arc fault features are not that satisfying in higher frequency bands after directly applying the existing Db9 based wavelet transform, causing the arc fault detection problem. Next, arc fault features are enhanced in most frequency bands by conducting the proposed Rbio3.1 based wavelet transform. Finally, the stochastic resonance (SR) method is proposed to further enhance Rbio3.1-based arc fault feature. The compared results prove that the combination between SR method and Rbio3.1 wavelet transform show the effective feature enhancement ability facing weak PV series arc fault electrical signals with different inverters and resistors.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129818945","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307917
Larkin Crilly, R. Jackson, Samuel Bond, G. Mills, Suvrat Bhargava
Electrical systems depend upon the reliable operation of electrical contacts or connectors. Such connectors may be found in environments running the gamut from climate-controlled spaces (i.e. personal computers) to extreme environments such as near the engine of a car and can be subject to degradation and failure through wear, corrosion, and other mechanisms. Liquid lubricants are sometimes used to mitigate these effects but are often nonconductive or otherwise do not protect the contact from degradation, causing a risk of excessive electrical contact resistance changes. Silver nanoparticles within dodecane have been investigated in prior research as a possible method to reduce these contact resistance changes and improve friction/wear characteristics. Further studies have been conducted to characterize the friction, wear, and contact resistance properties for a dodecane-based nanolubricant at a lower force more suited for smaller contacts and for comparison to a proprietary high viscosity hydrocarbon lubricant designed for use within electrical contacts.
{"title":"An Investigation of the Electrical Contact Resistance Change, Lubrication, and Wear Properties of a Nanolubricant","authors":"Larkin Crilly, R. Jackson, Samuel Bond, G. Mills, Suvrat Bhargava","doi":"10.1109/HLM49214.2020.9307917","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307917","url":null,"abstract":"Electrical systems depend upon the reliable operation of electrical contacts or connectors. Such connectors may be found in environments running the gamut from climate-controlled spaces (i.e. personal computers) to extreme environments such as near the engine of a car and can be subject to degradation and failure through wear, corrosion, and other mechanisms. Liquid lubricants are sometimes used to mitigate these effects but are often nonconductive or otherwise do not protect the contact from degradation, causing a risk of excessive electrical contact resistance changes. Silver nanoparticles within dodecane have been investigated in prior research as a possible method to reduce these contact resistance changes and improve friction/wear characteristics. Further studies have been conducted to characterize the friction, wear, and contact resistance properties for a dodecane-based nanolubricant at a lower force more suited for smaller contacts and for comparison to a proprietary high viscosity hydrocarbon lubricant designed for use within electrical contacts.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126988076","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307862
Chao Zhang, W. Ren, Guotao Wang
Interactions between neighboring asperities play an important role in evaluating the contact status accurately during the loading process for rough surfaces. In this paper, a three-dimensional finite element model considering interactions between two asperities is built for electrical contact analysis. Based on the simulation, effects of contact radii of a-spots and horizontal spacing between asperities on the contact area and contact resistance are investigated explicitly. The simulation results are compared with the theoretical results ignoring interactions for the same parameters. Furthermore, the critical conditions of considering interactions between asperities are determined. In addition, curve-fit equations for dimensionless contact resistance including the influence of asperity interactions are presented, which could be directly applied to the analysis for the rough surfaces in contact.
{"title":"A Finite Element Method to Investigate Electrical Contact Behaviors Considering Asperity Interactions","authors":"Chao Zhang, W. Ren, Guotao Wang","doi":"10.1109/HLM49214.2020.9307862","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307862","url":null,"abstract":"Interactions between neighboring asperities play an important role in evaluating the contact status accurately during the loading process for rough surfaces. In this paper, a three-dimensional finite element model considering interactions between two asperities is built for electrical contact analysis. Based on the simulation, effects of contact radii of a-spots and horizontal spacing between asperities on the contact area and contact resistance are investigated explicitly. The simulation results are compared with the theoretical results ignoring interactions for the same parameters. Furthermore, the critical conditions of considering interactions between asperities are determined. In addition, curve-fit equations for dimensionless contact resistance including the influence of asperity interactions are presented, which could be directly applied to the analysis for the rough surfaces in contact.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123944835","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307866
J. You, Rao Fu, Huimin Liang, Jiahe Zhang, Xiangdong Feng
Hermetical Seal Eletromagnetic Relay (HSER) is a kind of commonly used actuator in aerospace, aviation and industrial control systems. As a common working condition, it’s reliability under long-term continuous load directly determines the stable operation and safety of the system. This paper analyzes the basic operation principle of HSER, and establishes the calculation model of static and dynamic characteristics. The reason of HSER’s long-term failure is that the electromagnetic force and counter force provided by permanent magnet deteriorate under the effect of soft magnetic environment aging, the contact resistance increases, the temperature rises and then accelerates the failure cycle until HSER fails. According to IEC62506, the accelerated test system is established. Based on the virtual prototype model, the life prediction model is established under the support of test data. Taking a HSER as an example, the failure threshold is analyzed, the failure mode is predicted.
{"title":"Failure Simulation and Analysis Method of Hermetically Sealed Eletromagnetic Relay under Long-term Load","authors":"J. You, Rao Fu, Huimin Liang, Jiahe Zhang, Xiangdong Feng","doi":"10.1109/HLM49214.2020.9307866","DOIUrl":"https://doi.org/10.1109/HLM49214.2020.9307866","url":null,"abstract":"Hermetical Seal Eletromagnetic Relay (HSER) is a kind of commonly used actuator in aerospace, aviation and industrial control systems. As a common working condition, it’s reliability under long-term continuous load directly determines the stable operation and safety of the system. This paper analyzes the basic operation principle of HSER, and establishes the calculation model of static and dynamic characteristics. The reason of HSER’s long-term failure is that the electromagnetic force and counter force provided by permanent magnet deteriorate under the effect of soft magnetic environment aging, the contact resistance increases, the temperature rises and then accelerates the failure cycle until HSER fails. According to IEC62506, the accelerated test system is established. Based on the virtual prototype model, the life prediction model is established under the support of test data. Taking a HSER as an example, the failure threshold is analyzed, the failure mode is predicted.","PeriodicalId":268345,"journal":{"name":"2020 IEEE 66th Holm Conference on Electrical Contacts and Intensive Course (HLM)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122886425","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 : 2020-09-30DOI: 10.1109/HLM49214.2020.9307888
N. Fukuda, K. Sawa, T. Ueno
A brush-slip ring system is a mechanism used to transfer electrical current between stationary and moving parts. This mechanism is widely used, mainly in the excitation mechanisms of AC rotating machines. In recent years, the diversification in brush-slip ring systems has been remarkable. The usage range of these systems has extended to automotive alternators and grounding mechanisms for electric railways. Therefore, brush-slip ring systems require maintenance cost savings and greater reliability. To date, copper-based materials have generally been used for slip rings. Recently, because of advantages in terms of mechanical strength and cost, slip rings based on steel are being used increasingly. However, the sliding contact energization characteristics of steel slip rings have not yet been determined. In this work, contact voltage drop-brush current (V-I) characteristic tests were conducted using a steel slip ring and silver (Ag)-graphite brushes to determine the electrical characteristics of this system. As a result, an increased contact voltage drop was shown to be suppressed at a brush current of approximately 4–6 A. Then, based on the contact voltage drop at this time, the maximum temperature in the area between the slip ring and the brush was calculated using the φ-θ theory. As a result, we have shown that the nonlinearity of the V-I characteristics in the steel slip rings is associated with the steel transformation point. In addition, the maximum temperature point transition during the change in the brush Ag content is determined.
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