{"title":"Arc discharge and surge suppression during a breaking operation of a magnetic relay","authors":"H. Honma, S. Kimura, K. Shoji, N. Wakatsuki","doi":"10.1109/HOLM.2007.4318230","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318230","url":null,"abstract":"In a switching circuit with an inductive load, arc discharge and surge generated during a breaking operation are big problems. We proposed an electric method for arc discharge suppression using a timely controlled transient current switch and a capacitor arranged in parallel to the energizing switch. In this paper, we propose an improvement. We replaced the capacitor with two capacitors. One to suppress arc ignition and the other is to suppress surge. Using electrical measurements of the relay contact operation, adequate capacitance values and series resistance were derived numerically. The capacitance to suppress arc ignition does not depend on load inductance but only on load resistance. However, the capacitance and its series resistance to suppress surge depend on the load inductance and its resistance. For the break operation (50 V/8 A) of a conventional magnetic relay (HH62P) with an inductive load (84 mH), a 1muF capacitor can suppress arc ignition and a 100 muF capacitor and a resistance of 8Omega is sufficient to suppress surge. No arc ignition and surge controlled to less than 30 V were confirmed experimentally.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75768743","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}
{"title":"The Effect of Contact Closure in Vacuum with Fault Current on Prestrike Arcing Time, Contact Welding and the Field Enhancement Factor","authors":"P. Slade, R. Kirkland, E. Taylor","doi":"10.1109/HOLM.2007.4318191","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318191","url":null,"abstract":"Experiments were performed with vacuum interrupters containing Cu-Cr (25 wt%) and W-Cu (10 wt%) contacts. The vacuum interrupters were placed in a spring mechanism, which was placed in a tuned, capacitor bank electrical test circuit. The capacitor bank was charged to 25 kV, which allowed a symmetrical fault current of 50 kA (peak) at 30 Hz. As the vacuum interrupter's contacts closed a prestrike arc occurred when the contact spacing was small enough. This contact gap was recorded. The prestrike arc initiated the ac current, which was interrupted by the test circuit after one half cycle. The contacts were then opened with no current. This process was repeated 5 times. As the experiment progressed the prestrike arcing time increased; i.e. the contact gap broke down at larger and larger gaps during the closing operation resulting in longer and longer prestrike arcing times. We explained this phenomenon by considering the effect of the prestrike arc and the subsequent contact welding on the surface structure of the contacts. The change in the contact's surface structure resulted in an increase of the field enhancement factor, which, in turn, led to the vacuum breakdown of the contacts at increasing contact gaps. For the Cu-Cr contacts the prestrike arcing time was eventually long enough that the contacts formed a weld that the mechanism could not break. Although the prestrike arcing time with the W-Cu contacts did increase, the mechanism always broke any welds that formed.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78258447","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}
{"title":"The RAS Implications of DIMM Connector Failure Rates in Large, Highly Available Server Systems","authors":"T. J. Dell","doi":"10.1109/HOLM.2007.4318226","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318226","url":null,"abstract":"The juxtaposition of low-cost dual inline memory module (DIMM) connectors in highly reliable servers has created a difficult reliability, availability, and serviceability conundrum: the connector cost must be low enough to allow hundreds of sockets to be used per system, while at the same time, the system-level reliability must be high enough to prevent connector-related memory failures. This paper explores some of the modeling techniques that can be used to guide system-level fault tolerance decisions in view of the propensity of card-edge connectors to experience corrosion-induced failures, and it explains why understanding the probability density function (PDF) of the connector failure rate is crucial in establishing the system RAS strategy for DIMM connectors. The effects of both a \"low\" and \"high\" contact failure rate are analyzed at two different PDF's, and the resultant system implications are discussed.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86692001","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}
{"title":"Arc Fault Detection and Discrimination Methods","authors":"C. Restrepo","doi":"10.1109/HOLM.2007.4318203","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318203","url":null,"abstract":"Arc waveform characteristics can be evaluated with various methods to recognize the presence of hazardous arc fault conditions. Discussion covers the arc phenomena and how it is generated in a low voltage electrical distribution circuit, as well as the isolation of the presence of hazardous conditions versus conditions that could falsely mimic the presence of an arc fault. Many waveform characteristics and conditions support the detection of hazardous arc faults and foster a more robust design, capable of withstanding unwanted tripping conditions.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87900930","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}
{"title":"Dynamic Characteristic and Contact Bounce Analysis for an AC Contactor with PWM Controlled Coil","authors":"Yingyi Liu, Degui Chen, Liang Ji, Yingsan Geng","doi":"10.1109/HOLM.2007.4318232","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318232","url":null,"abstract":"In the optimum design of AC contactors, it is important to analyze the dynamic behavior. Moreover, movable contact and core bounces have remarkable effect on the lifetime of contactors. According to a kind of intelligent contactor with feedback mechanism, this paper builds two different sets of periodically inter-transferred equations. The equations describe the coupling of the electric circuit, electromagnetic field and mechanical system taking account of the influence of friction. And with virtual prototyping technology, the dynamic behavior of the contactor can be obtained. The paper introduces the contact resistance to investigate the bounce of the contact.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81224607","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}
A. Mutzke, T. Ruther, M. Kurrat, M. Lindmayer, Ernst-Dieter Wilkening
{"title":"Modeling the Arc Splitting Process in Low-Voltage Arc Chutes","authors":"A. Mutzke, T. Ruther, M. Kurrat, M. Lindmayer, Ernst-Dieter Wilkening","doi":"10.1109/HOLM.2007.4318213","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318213","url":null,"abstract":"Investigations on the arc splitting process in low- voltage arc chutes have shown that a threshold voltage has to be exceeded before new arc roots form. When an arc spot has been formed, the electrode fall is nearly constant and rather independent of the current. In simulations a thin layer of elements with a nonlinear current density-voltage characteristic surrounding the splitter plate represents the formation of new arc roots. To model this behavior a characteristic with a voltage hump at low current densities and a constant final voltage at higher current densities has been presented in former publications. In this paper, the influence of the magnitude of the voltage hump is studied. A lower voltage hump yields a smaller arc loop around the front edge of the splitter plate and an earlier subdivision of the arc. A too high voltage hump makes arc splitting impossible. A comparing simulation without any arc root model, but only with the properties of the metallic plates, shows that a realistic simulation of the arc splitting process needs special treatment of the arc roots. The results are compared and verified on the basis of experimental results. Hence, the arc splitting process is analyzed concerning arc voltage and current through the plate as well as location of the arc roots.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89470821","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}
M. Reichart, A.R. Neuhaus, C. Schrank, S. Ilincic, G. Vorlaufer
{"title":"The influence of design parameters on contact interlocking caused by material transfer","authors":"M. Reichart, A.R. Neuhaus, C. Schrank, S. Ilincic, G. Vorlaufer","doi":"10.1109/HOLM.2007.4318224","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318224","url":null,"abstract":"Contacts, switching DC loads, can create material transfer pip and crater formations which may cause non opening faults due to interlocking. Both, the material transfer formation and the capability to open the contacts at pronounced material transfer, are affected by the design parameters of the contact system. Since the decoupling of these two phenomena cannot be carried out in experimental investigations, a variation of design parameters without a changed material transfer formation is generally not possible. Therefore a finite element model of a contact system, similar to a mass-produced relay, with simple predetermined material transfer on the contacts was designed. By simulating the dynamic opening process and calculating relevant physical quantities (e.g. the separation force) the influence of certain design parameters on the opening capability was investigated. The calculations showed essential dependencies of the required force to open the contact system on certain design parameters. Although for real switches there is not a predictable interdependence between the widely scattering material transfer formation and the opening capability, the calculation can assist to optimize a well-defined switchgear design if material transfer is assumed.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86197291","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}
{"title":"Thermal Analysis of Sealed Electromagnetic Relays Using 3-D Finite Element Method","authors":"Huimin Liang, Wenlong Wang, G. Zhai","doi":"10.1109/HOLM.2007.4318227","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318227","url":null,"abstract":"Up to now, it is difficult to test the inner temperatures of sealed electromagnetic relays. In this paper, the temperature distribution of a sealed electromagnetic relay is obtained by using 3-D finite element analysis. The quality of thermal simulation results depends on the accuracy of both the modeled heat sources and heat sinks. Due to the high performance requirements of sealed electromagnetic relay it is interesting to know not only the temperatures of the conducting parts but also the thermal impact on the plastic components. Therefore, the non-metallic parts of the sealed electromagnetic relay (including the air within the device) are now part of the model. In order to improve the accuracy of simulation, the contact radius is calculated in advance. The relationship between convection heat transfer coefficient and temperature and how to consider connecting wires boundary condition are also researched here. Finally, the temperature distribution of a sealed electromagnetic relay is obtained by this method. Comparisons with experimental results confirm its validity.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75631997","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}
{"title":"Basic Investigations for Switching of RF Signals","authors":"W. Johler","doi":"10.1109/HOLM.2007.4318222","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318222","url":null,"abstract":"A major advantage of electromechanical RF relays is their capability to carry and to switch signals from DC up to the GHz range. Up to now the switching capability of miniature RF relays was limited to a few Watts, which was not really satisfactory. Basic investigations were performed to understand the mechanism when high frequency signals are switched, as no data was previously available. When high frequency signals are interrupted, the arc performs like a DC arc due to its thermal characteristics and burns for several periods of the signal. The arc is an adjustable resistor and just changes the amplitude of the output signal. When the contact gap increases, the arc finally extinguishes at current zero in a similar way as an AC arc. At the time the arc extinguishes the signal makes a phase shift as the open contact can be considered to be a capacitance. Practical tests were performed on a new type of high performance low-cost ultra-miniature RF relay with DC loads up to 60 W, low frequency AC loads up to 62.5 VA and RF loads with a maximum power of 37 W. The results obtained confirm the theoretical approach. Major advantages of bridge contacts providing two contact gaps in series were found, yielding excellent RF characteristics as well as outstanding switching performance in all frequency ranges from DC to RF. Even after 1 million operations no relevant changes of the RF characteristics were found, although a load of 37 W was hot switched.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88986435","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}
{"title":"Analyzing Method of Random Vibration Characteristic for Armature System of Hermetically Sealed Electromagnetic Relay","authors":"Zhai Guofu, C. Yinghua, Ren Wanbin","doi":"10.1109/HOLM.2007.4318214","DOIUrl":"https://doi.org/10.1109/HOLM.2007.4318214","url":null,"abstract":"The vibration performance of hermetically sealed electromagnetic relay which contains armature system is an important element when we judge the reliability of apparatus. A nonlinear single-degree-of-freedom mathematic model considering contact loss was built in this paper, and the dynamic behavior of armature subjected to external Gaussian white noise excitation was investigated by using Fokker-Planck equation and Monte Carlo simulation. Both the spectral contents and statistical results of the contact force showed great coincidence with reality. From the statistical results and spectral diagrams, the relation between the probability of loss contact, model parameters and system behavior was discussed, and the conclusions are of great importance for the reliability design of hermetically sealed electromagnetic relay.","PeriodicalId":11624,"journal":{"name":"Electrical Contacts - 2007 Proceedings of the 53rd IEEE Holm Conference on Electrical Contacts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89602411","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}