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Electrical Contacts, 1992., Proceedings of the Thirty-Eighth IEEE Holm Conference on

Date 18-21 Oct. 1992

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Displaying Results 1 - 25 of 34
  • Prediction of connectors long term performance from accelerated thermal aging tests

    Publication Year: 1992, Page(s):257 - 263
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (622 KB)

    The authors discuss surface films and report their effects on the long-term electrical stability of contacts, based on thermal aging tests. The surface films discussed are: residual plating salts, tin oxide, and tin oxide in the presence of lubricant. Surface film effects are found to be detrimental to the performance of electrical connectors because they lead to increases in low-level contact res... View full abstract»

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  • Environmental testing of elastomeric connectors

    Publication Year: 1992, Page(s):249 - 255
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (397 KB)

    The electrical performance of metal-in-elastometer connectors is evaluated for chip-on-board applications. Flowing mixed gas (FMG) class-II corrosion and dust tests are performed in accelerated conditions to simulate the long-term operating life of connectors in office-type environments. To explore the functional limits, the connectors are also tested in FMG class-III conditions, which simulate in... View full abstract»

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  • Making contact to aged surfaces

    Publication Year: 1992, Page(s):237 - 248
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (652 KB)

    A Monte Carlo analysis of aged crossed rod copper contacts is conducted to evaluate the effects from a number of variables such as film thickness, contact force, microhardness and geometry. The analysis is conducted using two models that employ material properties and design parameters as constraints in a statistical model of degradation. It is shown, using a power law model to describe the surfac... View full abstract»

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  • The effects of design variables and surface films on the contact resistance of copper-copper contact interfaces

    Publication Year: 1992, Page(s):219 - 235
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1016 KB)

    Studies are made on the effects of contact normal force, wipe, geometry, and hardness on cylindrical copper-copper contacts. The results show a complex interaction among the variables in determining whether reliable, metallic asperity contact can be established. No straightforward relationship among the variables is established, and no conclusion is reached concerning the effects of any single var... View full abstract»

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  • Study of ion implanted arcing contacts

    Publication Year: 1992, Page(s):213 - 218
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (330 KB)

    The study of arc on break is a useful tool for finding an optimum implanting technology to increase the reliability and lifetime of contacts. Argon ions or boron ions were implanted into AgMgNi contact material, and arc duration and erosion were measured. The results show that the arc duration and erosion are reduced as compared to unimplanted contacts. It is found that the ion implanted contacts ... View full abstract»

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  • An experimental investigation of the dynamic contact characteristics on the relay contacts

    Publication Year: 1992, Page(s):209 - 212
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (269 KB)

    An investigation of the dynamic contact characteristics of NO (normally open) and NC (normally closed) relay contacts is presented. The contact voltage V/sub c/=f(t) versus the contact resistance during the contact closing process is employed. After the relay contacts impact, they do not reach the stable make position at once, but undergo two processes, i.e., contact bounce and contact resistance ... View full abstract»

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  • EPROM-based overcurrent relays

    Publication Year: 1992, Page(s):203 - 207
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (220 KB)

    A very simple and inexpensive time-overcurrent relay is reported. The relay is implemented using EPROM, a binary counter, a digital to analog converter, an analog comparator, and logic gates. As an extension of the work, the implementation of a multicurve time-overcurrent relay is reported. The switching of only four relays has been considered in this implementation. If required, the implementatio... View full abstract»

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  • The failure mechanism of low-voltage electrical relays

    Publication Year: 1992, Page(s):191 - 202
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (814 KB)

    The mechanism of increase in the resistance of low-voltage electrical contacts with the number of on-off switch cycles is investigated. Experiments are conducted at room temperature on Au and a number of base metals (Ni, Fe, Ti and Sb) in mixtures of air and organic vapors (benzene, toluene and xylene). The increase in contact resistance is found to be primarily due to carbon formation on the cont... View full abstract»

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  • Contact properties of the spring probe for probing on a solder bump

    Publication Year: 1992, Page(s):187 - 190
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (430 KB)

    Flip-chip solder bumps are formed on the area array electrodes of high-speed computer LSI chips. A high-density spring probe (600 probes/9 mm*9 mm) was developed for testing these LSIs by vertical insertion into the solder bumps. Solder with an extremely high lead content is used to lengthen the life for the soldered joint. This oxidized lead with high resistivity causes poor contact. Probing test... View full abstract»

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  • Influence of mineral silicon containing deburring media on contact resistance of fine silver rivets

    Publication Year: 1992, Page(s):181 - 186
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (775 KB)

    Embedment of mineral silicon (SiO/sub 2/) introduced by deburring electrical contacts inhibits metallic conduction. The concentration of mineral silicon (SiO/sub 2/) on fine silver contacts submitted to deburring in an open tumbler and harperizing for specific time intervals is investigated to assess the factors contributing to low contact resistance in dry circuit applications. When arcing, quick... View full abstract»

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  • A study of contamination levels measurement techniques, testing methods, and switching results for silicon compounds on silver arcing contacts

    Publication Year: 1992, Page(s):173 - 180
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (851 KB)

    Silicon compounds, both inorganic and organic, are detrimental contaminants for arcing electrical contacts. The authors review past work and introduce new data correlating contamination levels with switching performance. Methods for measuring silicon contamination on the contact surface by use of an energy dispersive X-ray analyzer (EDXA) are described. The difference in mechanisms with both miner... View full abstract»

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  • The study of the relationship between arc duration and arc energy of relay and microswitch contacts

    Publication Year: 1992, Page(s):167 - 172
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (318 KB)

    Under conditions of varying the load current, time constant, or other parameters, the arc duration and arc energy of relay and microswitch contacts at make and break are accumulated by means of microcomputer control and a high-speed sampling system. The influence of the variation of parameters on the arc duration and arc energy is analyzed. The relationship between arc duration and arc energy at b... View full abstract»

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  • Measuring molded case circuit breaker resistance

    Publication Year: 1992, Page(s):159 - 165
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (431 KB)

    Molded case circuit breaker resistance is measured under various conditions to demonstrate the need for more standardized procedures when performing millivolt drop measurements. Breakers, rated at 600 V/sub ac//250 A/sub ac/ and 120/240 V/sub ac//50 A/sub ac/, with silver-tungsten (Ag-W) contacts are used to show that contact resistance can cause variability in circuit breaker resistance and to de... View full abstract»

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  • Improved sliding electrical brush performance through the use of water lubrication

    Publication Year: 1992, Page(s):149 - 155
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (385 KB)

    Electrical and wear performances of sliding electrical currents are critically dependent on the local contact spot temperature resulting from Joule and frictional heating. A method of water application for both lubricating and cooling significantly decreases wear rates. Increases in the useable current densities in continuous operation are achieved with metal fiber brushes. Brush polarity has a di... View full abstract»

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  • Measurement and prediction of brush interface temperature at sliding electrical contacts

    Publication Year: 1992, Page(s):143 - 148
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (540 KB)

    Binderless copper-graphite composite electrical brushes have been fabricated with a high-energy and high-rate pulse sintering technique. Experiments were conducted to measure the interface contact spot temperatures of homopolar pulse consolidated brushes for a rotor surface sliding speed of 40 m/s, an apparent brush current density of 180 A/cm/sup 2/, and a brush down force of 44.5 N. Thermocouple... View full abstract»

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  • Sliding contact characteristics between self-lubricating composite materials and copper

    Publication Year: 1992, Page(s):135 - 142
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (534 KB)

    Simultaneous measurements of contact electric resistance and coefficients of friction on three types of composite materials containing laminar solid lubricants were conducted. Contact resistances of new composite materials (CM-4, CM-5) were as low as 1/10, compared to those of a previously prepared composite material (CM-1) in the range of the measurement conditions (50-1000 gf, 0.1-10 A). Coeffic... View full abstract»

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  • Performance testing of a low current sliding contactor system

    Publication Year: 1992, Page(s):125 - 133
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1431 KB)

    Two tests designed to evaluate the electrical and mechanical performance of low current sliding contactor/counterface pairs in oscillatory motion are described. Test parameters were chosen to provide an accelerated test of materials used in automotive throttle position sensors based on the mechanical exposure of these sliding contact interfaces. Features of the test systems are discussed as they r... View full abstract»

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  • Cd-free silver alloy for sliding contact

    Publication Year: 1992, Page(s):119 - 124
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (631 KB)

    A new silver alloy containing Li and La(ALL alloy) was developed for use as a sliding contact material. This alloy can replace the silver alloy containing 1% of Cd (AgCd1) for light duty sliding contacts because of its high performance. An investigation was conducted on the fretting test to evaluate the required characteristic properties of the sliding contact. Ag-La-In-Ni, Ag-La-In-Sb, Ag-Li-In, ... View full abstract»

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  • Field observations of residential service panel connections and components

    Publication Year: 1992, Page(s):113 - 118
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (972 KB)

    As part of home inspection procedures, 1052 residential electric services were examined in southern New York between 1987 and 1991. A study of the field observations revealed frequent occurrences of corroded, burned, and damaged connections and corroded and malfunctioning circuit breakers. Causative factors noted in the service environment include presence of moisture and poor installation practic... View full abstract»

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  • Environmental deterioration of aluminum-aluminum connections

    Publication Year: 1992, Page(s):105 - 111
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (624 KB)

    Wire splice connections are investigated for deterioration due to environmental factors. The tested splices of solid aluminum and copper wires are made using twist-on connectors. Some specimen groups are exposed in a chamber at 35 degrees C and 90% relative humidity. Additional groups are exposed for ten years to a normal application environment. There is no current flow except when potential drop... View full abstract»

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  • Effect of an axial magnetic field upon the development of the vacuum arc between opening electric contacts

    Publication Year: 1992, Page(s):95 - 103
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (653 KB)

    Two series of experiments are reported. In the first, a Helmholtz coil provides an independent, constant axial magnetic field B/sub ax/ in the gap between opening Bruce profile, chromium-copper (Cr-Cu) contacts. Peak arc currents up to 40 kA at 50 Hz are studied with B/sub ax/ up to 112 mT. For each peak current, a critical field B/sub crit/ is determined above which anode spots did not form. For ... View full abstract»

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  • Anti-welding property and fracture mechanism of CuCr contact materials

    Publication Year: 1992, Page(s):91 - 94
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The welding strengths of different CuCr contact materials are measured and the fracture morphologies are observed by scanning electron microscope. Experimental results show that carbon added to CuCr alloys can improve the anti-welding property. Carbide films on the surface of Cr particles reduce the fracture stress of CuCr alloys and influence the microstructure of the weld zone.<> View full abstract»

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  • Influence of contact surface conditions on discharge phenomena of vacuum reed switches

    Publication Year: 1992, Page(s):87 - 90
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (258 KB)

    The relationship between contact surface conditions and discharge phenomena of vacuum reed switches is studied. Switches are examined before and after surface deactivation treatment. Breakdown voltage is increased by the surface deactivation treatment. Work function is also found to be enhanced by the treatment. Rhodium oxide film is produced on the contact surface through the surface deactivation... View full abstract»

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  • Vibroimpact in electrical contact pair and its dynamic contact resistance

    Publication Year: 1992, Page(s):79 - 85
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (508 KB)

    The electrical contactor bounce should be treated as a vibroimpact problem, i.e. a strongly nonlinear or catastrophic one. A rigid impact model with a coefficient of restitution is adopted. The contact is regarded as a deformable body. The author proposes linearizing the elastoplastic impact behavior of the contactors, suggests a bilinear vibration model of the contactor bounce, and the use of a s... View full abstract»

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  • Theoretical study of factors influencing arc erosion of cathode

    Publication Year: 1992, Page(s):71 - 78
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (513 KB)

    A theoretical model describing the influence of the arc condition and the cathode material and geometry on arc cathode erosion has been formulated. To arrive at a self-consistent description for the entire arc cathode attachment region, a realistic, one-dimensional sheath model is used. This sheath model is supplemented by an integral energy balance of the ionization zone between the sheath and th... View full abstract»

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