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Electrical Contacts, 2008. Proceedings of the 54th IEEE Holm Conference on

Date 27-29 Oct. 2008

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Displaying Results 1 - 25 of 66
  • [Title page i]

    Publication Year: 2008 , Page(s): a
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  • [Title page ii]

    Publication Year: 2008 , Page(s): i
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  • [Copyright notice]

    Publication Year: 2008 , Page(s): ii
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  • Contributors page

    Publication Year: 2008 , Page(s): iii
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  • Steering Committee

    Publication Year: 2008 , Page(s): iv
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  • Officers

    Publication Year: 2008 , Page(s): v
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  • Table of contents

    Publication Year: 2008 , Page(s): vi - xiv
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  • Foreword

    Publication Year: 2008 , Page(s): xv
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  • Ragnar Award

    Publication Year: 2008 , Page(s): xvi - xvii
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  • Morton Atlar Lecture

    Publication Year: 2008 , Page(s): xviii
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  • Erle Shobert Prize paper

    Publication Year: 2008
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  • THE ARMINGTON RECOGNITION AWARD

    Publication Year: 2008 , Page(s): xxi
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  • High Current AC Break Arc Contact Erosion

    Publication Year: 2008 , Page(s): xxii - xlvi
    Cited by:  Papers (2)
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  • The Transition from to the Metallic Phase Arc After the Rupture of the Molten Metal Bridge for Contacts Opening in Air and Vacuum

    Publication Year: 2008 , Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (806 KB) |  | HTML iconHTML  

    The total arcing time between opening electrical contacts interrupting a low voltage, low current circuit in both air and vacuum was controlled. The voltage across the opening contacts showed the rupture of the molten metal bridge and then its rapid increase to a value greater than the minimum arcing voltage before dropping back to a value close to the minimum arcing voltage. Using a radioactive tracer technique it was observed that at very short arcing times there was an anomalous net transfer of contact material to the cathode. As the arcing time increased this cathode gain decreased before increasing again at longer arcing times. High-speed streak photographs of contacts opening in air at higher currents showed an initial shock wave that resulted from the rupture of the molten metal bridge and before the formation of the metallic phase arc. Similar photographs of contacts opening in vacuum showed the initiation of a metal phase arc in the region of the ruptured molten metal bridge. After the rupture of the molten metal bridge, the voltage across the contacts rose very rapidly to a value of a few 10's of volts before dropping back to a minimum value. These data will be used to discuss the rupture of the molten metal bridge, the formation of the pseudo arc in the high-pressure metal vapor resulting from the bridge rupture and the eventual development of the metallic phase arc. View full abstract»

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  • An Electrical Arc Erosion Model Valid for High Current: Vaporization and Splash Erosion

    Publication Year: 2008 , Page(s): 9 - 14
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    Electrical arc erosion plays an important role in limiting the life of power switching devices. Consequently, a macroscopic arc erosion model, valid for high current, has been developed. This is the first of its kind since it takes into account two modes of contact material erosion: vaporization and splash erosion. Specifically, this model is used to measure the amount of contact material removed after one electrical discharge. It, therefore, allows the comparison of electrical contact erosion resistances between materials. Furthermore, this model is the first step in determining the composition of a suitable AgCdO substitute by identifying the most influential material properties in the arc erosion process. View full abstract»

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  • Melting Phenomena and Arc Ignition of Breaking Relay Contacts

    Publication Year: 2008 , Page(s): 15 - 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1293 KB) |  | HTML iconHTML  

    Using the transient current switch circuit in parallel with the energizing switching contacts and the driving delay lines for timely control of breaking operations, the increase of contact voltage is suppressed as well as arc ignition at the last stage of the breaking electric contacts. Therefore, the melting phenomena can be slowly controlled and the electric characteristics can be accurately measured. Breaking contact voltage Vc and current Ic of conventional electromagnetic relays with Ag contacts were measured for two hinge springs (Spring constants; 2 N/mm and 0.2 N/mm), for 12.5~50 V energizing power-supply voltage and for 0.1~20 A contact current. The current-decreasing process was clearly measured at the melting voltage Um. After the melting voltage, the breaking time of contact current did not depend on mechanical conditions due to the two springs and energizing power-supply voltage, but did depend on the contact current. A new melting model of breaking mechanical contact is proposed. Using the model, a numerical equivalent circuit analysis of electric characteristics confirmed the measured data. For the conventional breaking operation (50 V/1A), arc ignition was measured after the melting break operation. The top of the metal contact had a finely shaped hemisphere and arc was ignited only once. The residue of arc ignition was observed as a black concentric circle, which was clearly separated from the melt contact point. View full abstract»

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  • Characteristics of Break Arcs Driven by External Magnetic Field in a DC42V Resistive Circuit

    Publication Year: 2008 , Page(s): 21 - 26
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB) |  | HTML iconHTML  

    Break arcs occurring between electrical contacts are driven by the external magnetic field. Break arcs are observed using a high-speed camera. The external magnetic field is applied with a permanent magnet. The distance between the electrical contacts and the magnet is varied. Experimental circuit is DC 42 V-10 A resistive circuit. Material of electrical contacts is pure silver. The opening speed of electrical contacts is varied as 5, 10 and 20 mm/s. Following results are shown. The arc duration decreases with decrease of the distance between the electrical contacts and the magnet. When the magnetic-flux density applied by the external magnet is lower than a certain value at the center axis of the electrical contacts, the effect of the magnetic field to drive the break arc becomes ineffective to shorten the arc duration. The result is explained with a relationship between the motion of break arc and the distribution of the external magnetic field. View full abstract»

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  • A Finite Volume Scheme for Modeling Arc Discharges in Low Voltage Circuit Breaking Devices

    Publication Year: 2008 , Page(s): 27 - 34
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    In this document, a coupled system of codes will be presented that have the goal to simulate the transient arc movement in low voltage circuit breaker devices. A numerical method built on the basis of the finite volume scheme is described, that addresses convergence problems at the current-dependent potential jump at the interface between the arc and the electrodes. It is shown how different simulations can propagate, depending on the initial temperature profile that models individual ignition methods. Experimental and simulated data will be compared on simplified geometries, i.e. a geometry with straight runners, and a second geometry with one runner bent, exhibiting good qualitative agreement. View full abstract»

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  • High Temperature Resistant Gold Alloys for Switching Signal Relay Contacts

    Publication Year: 2008 , Page(s): 35 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (482 KB) |  | HTML iconHTML  

    Most telecom/signal relays are of the surface-mounted type nowadays. Since the introduction of lead-free soldering processes, the temperature exceeds 260degC during the soldering process. In a growing share of applications, these relays are additionally used in high-temperature environments such as motor compartments. Regardless of the high ambient temperatures of up to 125degC at which the relays are operated, there are unchanged requirements of the stability of the contact resistance, with target values of less than 10 mOmega deviation during the entire lifetime. In order to achieve low and stable contact resistance, the type of gold alloy and the way the gold layers are processed are of major importance. Sputtered and diffused gold layers showed better performance at high temperatures than rolled gold layers as well as gold alloys with no or very low concentration of non- precious metals. But not only the top layer has an impact; the base material too has a major impact on the contact resistance stability. PdRulO as base material resulted in much better contact resistance stability than AgNi20. When these contact materials are used in telecom/signal relays even at high ambient temperatures, extremely low and stable contact resistance values can be achieved for a long period of time. View full abstract»

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  • Effects of Electrical Contact Failure on High Speed Digital Signal Transmission

    Publication Year: 2008 , Page(s): 41 - 46
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    In digital communication systems, the deleterious effects of contacts at coaxial connector is one of the major causes of declining quality of communication. This paper describes the effects of contact degradation caused by contamination of a coaxial connector on transmitted signal integrity and error code rate. Transmission of high frequency current through degraded coaxial connectors is simulated and analyzed based on finite element method (FEM). An improved contact impedance model is introduced and its influence on high speed signal transmission is investigated. The impedance of degraded coaxial connectors is presented. The phenomena of contact failure which lead to error codes in signal transmission are confirmed in the experiments. View full abstract»

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  • Effect of Nanosecond Electrical Discontinuities in High-Speed Digital Applications

    Publication Year: 2008 , Page(s): 47 - 52
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2013 KB) |  | HTML iconHTML  

    Nanosecond discontinuities are a concern in separable-interface connectors. Speculation about their causes includes the structural movement between perfectly clean and flat contact surfaces and/or surface irregularities and presence of surface films. Both of these scenarios are considered here in the context of high-speed transmission (i.e. greater than 1 Gbit/s) in backplane connectors. Because such connectors have gold-to-gold mating surfaces, oxide-related discontinuities such as may occur with tin, silver, or aluminum interfaces are not considered. This paper considers the propagation speed of a stress wave to show the unlikelihood of nanosecond discontinuities arising due only to macroscopic structural shock and vibration. Thus, contact physics and the presence of contact imperfections, are required to cause nanosecond-level intermittences. Assuming that a discontinuity of one or several nanoseconds does occur, the short duration of the event permits only a minute separation between the two contact surfaces. This effect is equivalent to and modeled as the insertion of a very large series capacitor between the two conductors. At high frequencies, such a capacitor would behave quite similarly to a short circuit. Circuit simulations of a communication link and the resultant insertion loss and eye patterns show that these discontinuities do not disrupt high-speed data transmission. View full abstract»

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  • Numerical Prediction of Socket Solder Joint Reliability during Shock

    Publication Year: 2008 , Page(s): 53 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB) |  | HTML iconHTML  

    This paper proposes a simulation methodology to assess the risk in solder joint reliability (SJR) of Pin Grid Array (PGA)/ Land Grid Array (LGA) Socket during Mechanical shock. One of the main challenges in simulation is the complex socket/contact geometry convoluted with its massive number of degrees of freedom. This paper proposes a technique, Contact Isolation Method (CIM), to simplify the geometry so that it can be modeled with highly reduced degrees of freedom (DOFs) while still maintaining 90% of the in-plane and out-of-plane stiffness compared with the original structure. The Pin Grid Array 700 socket (PGA700) and Pin Grid Array 604 socket (PGA604) were used as case studies to demonstrate this methodology. A system model was completed for the PGA604 socket with a focus on its capability to assess SJR. A reasonable correlation between the modeling and experiment on the dynamic board strain demonstrates that this technique is viable. In addition, this paper verifies that the board strain is a proper metric for the risk assessment in SJR, and defines the optimal strain gauge location. The impact of the boundary conditions is also investigated. View full abstract»

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  • Innovative, Multifunctional Contact-Spring Design

    Publication Year: 2008 , Page(s): 59 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (545 KB) |  | HTML iconHTML  

    The connector industry is under increased pressure to innovate its products and reduce costs. For this reason it is no longer adequate only to use the latest development tools and strategies in order to implement new designs with increased speed and precision. It is also necessary to persuade the customer with added value by integrating multiple uses into the connector. An example details how the use of know-how transfer and principles of similarity can be used to transfer conventional connector principles from industrial electronics for use in innovative motion mechanisms in telecommunication applications. The application involves mechanics as well as electrical low and high frequency technology. View full abstract»

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  • Extension and Experimental Verification of a New 'First Contact' Method to Model Performance of Multilayer Contact Interfaces

    Publication Year: 2008 , Page(s): 66 - 73
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1567 KB) |  | HTML iconHTML  

    As the connector industry moves towards the use of smaller and smaller contact designs, achievable contact normal forces have been reduced to levels below what has been typically used previously in connector applications. Therefore, improving the ability to predict and analyze the mechanical and electrical performance of these lower force contact interfaces is becoming increasingly important. This paper will illustrate further development and experimental verification of a new method to simulate elastic/plastic contact between two multi-layered nonconforming rough surfaces. This new approach involves using six scale independent parameters to statistically model two 3-dimensional multilayered surfaces coming into contact. The mechanical and electrical response characteristics of all the layer materials, as well as frictional behavior at the contacting asperity surfaces, are taken into account as pressure is applied between the surfaces and the a-spot distribution is formed. The mechanical and electrical contact performance of the resulting interface are calculated and visualized in 3 dimensions. The model has been extended and applied to contacts with varying surface finish materials and surface topology characteristics. These results are then compared to experimental data generated from samples with comparable finishes. View full abstract»

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  • Investigation of Relaxation Behavior for Terminals of CPU Socket Connectors

    Publication Year: 2008 , Page(s): 74 - 77
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (137 KB) |  | HTML iconHTML  

    Terminals of a CPU socket connector dominate signal transmission between the CPU and the motherboard. Contact forces between the terminal of an electronic connector and the corresponding counterparts generally play an important role in signal transmissions. The contact forces of these terminals, however, could decay gradually due to the stress relaxation effect under the high temperature conditions. A finite element analysis is carried out to examine the relaxation phenomenon of the terminal in the present study. The strain-hardening form of the power-law creep model is adopted to account for the relaxation behavior of the terminal material. According to the field life acceleration test specifications established by the Electronic Industry Association (EIA), relationships between the calculated contact force and duration period are then constructed. Moreover, the contact force of the terminal subjected to thermal cycling test is also investigated. Calculations show that the decreased amount of the contact force is rather limited. Associated electrical resistances of the current terminal are further measured to validate the suitability of the contact force as an index of the signal transmission quality. View full abstract»

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