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Electrical Contacts, 1988., Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on

Date 26-29 Sept. 1988

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  • Electrical Contacts - 1988. Proceedings of the Thirty Fourth Meeting of the IEEE Holm Conference on Electrical Contacts (IEEE Cat. No.88CH2604-7)

    Publication Year: 1988
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    Freely Available from IEEE
  • The future of electrical switching contacts under the influence of electronics

    Publication Year: 1988 , Page(s): 3 - 11
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (557 KB)  

    After a short presentation of the principles of switching of electromechanical switches, transistors, MOSFETs, thyristors, triacs, and GTOs (gate turn-offs), the requirements for the different applications of switching devices are elucidated. The replacement of electromechanical switches by electronic ones is considered for energy distribution, energy in industry, control and regulation, for domes... View full abstract»

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  • Pure silver surface layer on the oxidized Ag-Sn-In material

    Publication Year: 1988 , Page(s): 13 - 15
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    One of the drawbacks of internally oxidized Ag-Sn-Al alloy is that a pure silver layer always appears on the oxidized material surface after oxidation. Although the thickness of the pure silver layer varies only between 0.0002 and 0.001 in. (0.005 to 0.025 mm), the silver layer always causes light tack welding in the early stage of a switching operation. The severity depends on the device's mechan... View full abstract»

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  • The effect of high temperature on the release of heavy metals from AgCdO and AgSnO2 contacts

    Publication Year: 1988 , Page(s): 17 - 30
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    An experiment was undertaken to study the release of heavy metals from AgCdO and AgSnO/sub 2/ contacts when they were subjected to high temperatures similar to those that would occur in a fire. Samples of AgCdO ( approximately 15 wt.% CdO) and AgSnO/sub 2/ ( approximately 15 wt.% SnO/sub 2/) were placed in a furnace and heated for 1 h at temperatures ranging from 800 degrees C to 1240 degrees C. T... View full abstract»

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  • The development of silver-based cadmium-free contact materials

    Publication Year: 1988 , Page(s): 31 - 35
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (960 KB)  

    A procedure is described that allows contact material compositions to be developed by a systematic progression through several levels of component evaluations and selections based on electrical test results. The testing and selection methodology is designed to develop the best contact material composition while also evaluating how changes in composition can be expected to alter the contact perform... View full abstract»

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  • Cracking mechanisms in Ag-SnO2 contact materials and their role in the erosion process

    Publication Year: 1988 , Page(s): 37 - 46
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    The authors present the results of an investigation conducted into the factors governing the erosion of Ag-SnO/sub 2/ electric contact materials by repeated electric arcing and the manner in which these factors are altered by chemical effects. Two features found to have major influences were the inhomogeneous interfaces between the Ag matrix and the SnO/sub 2/ granules, and the wetting characteris... View full abstract»

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  • Arc mobility on new and eroded Ag/CdO and Ag/SnO2 contacts

    Publication Year: 1988 , Page(s): 47 - 56
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (606 KB)  

    The mobility of break arcs in a magnetic blast-field was investigated in both a model switch and a commercial contactor. After contact separation, three arc motion phenomena were measured independently: initial reduced arc motion (immobility and creeping), subsequent running, and final commutation from the contacts to the arc runners. Contacts made from Ag/CdO and from Ag/SnO/sub 2/ were compared ... View full abstract»

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  • Evaluation of AgSnO2 material on high current DC switching

    Publication Year: 1988 , Page(s): 57 - 64
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1186 KB)  

    An experimental study was conducted to evaluate the performance of AgSnO/sub 2/ contacts (with 12 wt.% and 15 wt.% of SnO/sub 2/) for high-current DC switching. The contacts were tested in a solenoid-operated fixture equipped with an arc quenching chamber and an in-line magnetic blow-out system. The switching experiment was performed at 480 V DC with currents up to 1500 A. The duty cycle was two o... View full abstract»

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  • Electrical contact reliability: how is it determined?

    Publication Year: 1988
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (40 KB)  

    Summary form only given. There are at least two approaches to ensuring reliable connector performance. One is to require that a safety factor be built into the connector which provides some level of assurance of reliable performance. The second approach discussed here is the determination of reliability based on a statistical treatment of test data. To determine contact reliability using this appr... View full abstract»

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  • Statistical considerations in the estimation of electrical contact reliability

    Publication Year: 1988
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (38 KB)  

    Summary form only given. The established definition of reliability involves four key elements: probability, satisfactory performance, operating life, and operating conditions. Reliability of existing systems can be estimated using field data when they are available in suitable form and quantity, or using data from (often accelerated) laboratory tests. Test data are emphasized here. Such data take ... View full abstract»

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  • Design and calibration of appropriate connector qualification/reliability tests

    Publication Year: 1988
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (25 KB)  

    Summary form only given. Timely development of information on connector reliability requires development of calibrated, relevant laboratory tests. Development of such tests for connectors requires an understanding of the failure mechanisms active in a connector system. It is the goal of the test designer to think of all the things that might go wrong with the connector, and to design and calibrate... View full abstract»

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  • An analysis of field failure of passive and active components, including connectors

    Publication Year: 1988
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    Summary form only given, as follows. The author briefly describes current work on establishing and running an organization for the collection and analysis of field-failure data on passive and active components in electronic equipment. The data collection is described and the essential features are noted of the data format that is being used. Data have now been collected from all the sources for ne... View full abstract»

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  • The effects of the interaction of normal force and wipe distance on contact resistance in precious metal plated contacts

    Publication Year: 1988 , Page(s): 73 - 83
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (695 KB)  

    The effects of contact normal force and wiping distance on contact resistance were evaluated for hemispherical contacts wiping on flat coupons. Hard- and soft-gold-plated coupons and palladium and gold-over-palladium contacts were used. Two types of wiping action were investigated; wiping under the full normal force of 180 g and wiping during the application of the normal force. The coupon surface... View full abstract»

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  • Metallurgical study and tribological properties of edge card connector spring/tab interface

    Publication Year: 1988
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    Summary form only given, as follows. The influence of composite metallurgical structure on the tribological behavior of an edge-card connector was studied. The study centered on the metallurgy of the card tab, which is a multilayer structure consisting of a printed circuit board with an overplated copper layer, nickel, hard gold, and soft gold. These experiments were performed under both dry frict... View full abstract»

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  • Fretting corrosion of tin at elevated temperatures

    Publication Year: 1988 , Page(s): 87 - 91
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (434 KB)  

    Fretting corrosion of a tin-plated copper alloy was investigated over the temperature range up to 110 degrees C using a dimple-flat contact configuration. Results, based on contact resistance (CR) characteristics and scanning electron microscopy examination, revealed that room temperature corrosion results are not valid at elevated temperatures. Specifically, the corrosion rate as well as the stat... View full abstract»

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  • Effect of surface structure on the contact resistance measurements of electrodeposits

    Publication Year: 1988 , Page(s): 93 - 99
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (610 KB)  

    It has been demonstrated with gray nickel phosphorus alloy (Ni/P) deposits and with gray nickel (NiCl) deposits that achieving consistently low R/sub c/ using base metal deposits requires a surface morphology with a multitudinous number of tightly space asperities of uniform height. These asperities, on a microscopic (5000*) scale, can appear to be acicular star-burst or gritty (sand-like) and wil... View full abstract»

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  • Wear resistance of nickel and nickel phosphorus alloy electrodeposits

    Publication Year: 1988 , Page(s): 101 - 107
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (866 KB)  

    The wear resistance of gray Ni/Cl and Ni/P deposits was evaluated using a crossed-wire test method that stimulates the wear that develops on plug-in type printed wiring boards. All wear samples were lubricated with 2-wt.% five- or six-ring polyphenylether fluid. Some samples plated with a thin layer of cobalt-hardened gold were also examined. Wear test results showed that: (1) gray Ni/P deposits p... View full abstract»

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  • Electrical contact to superconductors

    Publication Year: 1988 , Page(s): 109 - 119
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (903 KB)  

    Electrical contacts to conventional superconductors and high-critical-temperature oxide superconductors are reviewed. The technologically important conventional superconductors considered are Nb and its alloys and compounds, the oxide superconductors are typified by YBa/sub 2/Cu/sub 3/O/sub 7/. Three distinct forms in which the superconductor can be fabricated are considered: thin films for electr... View full abstract»

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  • Application of silver-based contact materials in air-break switching devices for power engineering

    Publication Year: 1988 , Page(s): 121 - 127
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1119 KB)  

    The properties of some commonly used silver-based contact materials are discussed on the basis of the various metallurgical processes occurring in the interaction of the electric arc with the contact material. Using selected examples taken from research work and field experience, it is pointed out how the contact properties are influenced by the metallurgical mechanisms involved. Good results are ... View full abstract»

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  • Reciprocating motion of magnetically driven arcs in air at low critical atmospheric pressure

    Publication Year: 1988 , Page(s): 129 - 134
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (450 KB)  

    Using high-speed photography and an optical-fiber microcomputer system, a series of experimental investigations were performed on the motion of DC short arcs in a transverse magnetic field in air at low critical atmospheric pressure. It is shown that the cold cathode arc runs a long distance forward (ampere's direction) and backward (retrograde direction) without stop. This phenomenon is called re... View full abstract»

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  • Effect of the air pressure on the commutation delay of magnetically driven arcs across a gap or a stop in one of two parallel electrodes

    Publication Year: 1988 , Page(s): 135 - 139
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (312 KB)  

    Research on the effect of the air pressure on the commutation delay of magnetically driven arcs across a gap or a step in one of two parallel electrodes has been conducted using high-speed photography and an optical fiber microcomputer system. The experiments were carried out on different kinds of electrode material, such as brass, copper (cold cathode), and graphite (hot cathode). It is shown tha... View full abstract»

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  • Electrical contact bounce in medium duty contacts

    Publication Year: 1988 , Page(s): 141 - 149
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (595 KB)  

    The basic phenomena of electrical contact bounce with the passage of current, in the medium duty range (1 to 30 A AC and DC), are investigated. Experimental results presented show that by considering individual impacts, an understanding of how current affects contact bounce is achieved. An automated test system is used to evaluate contact bounce. The surface degradation is evaluated by endurance t... View full abstract»

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  • Electrical instabilities in stationary contacts: Al/Al and Al/brass junctions

    Publication Year: 1988 , Page(s): 151 - 165
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1080 KB)  

    Electrical instabilities in Al/Al and Al/brass stationary point junctions has been examined in ultrahigh vacuum and in oxygen gas. It is found that Al/brass junctions are electrically stable in vacuum and in oxygen gas if the surfaces are sufficiently clean. The growth of intermetallic compounds in this interface affects stability only after a sufficiently long exposure of the contact, typically s... View full abstract»

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  • Field experience and long-term stability of high current contacts

    Publication Year: 1988 , Page(s): 167 - 171
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (434 KB)  

    A large number of static electrical contacts were investigated with respect to their long-term stability of contact resistance. The contacts studied were of two types: (1) an aluminum to aluminum busbar contact, and (2) an aluminium to nickel-plated-copper clamped contact. Both contact types were subjected to the same electrical load: 500-1000 A, RMS. The contacts were operated in an indoor enviro... View full abstract»

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  • Conduction through surface films on aluminum wire

    Publication Year: 1988 , Page(s): 173 - 178
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (575 KB)  

    Conduction through undisturbed surface films on commercial aluminum wire is experimentally evaluated by establishing an area of contact on the wire surface without applying mechanical pressure, using a conductive silver epoxy. The measurements indicate the film conduction is substantially higher than has been estimated on the basis of the properties of pure aluminum oxide. Using applied electrical... View full abstract»

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