Study of Arc Mobility and Reignition in a Static Gap Discharge with Magnetic Field
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Microstructure effect on reignition and welding properties of copper-tungsten electric contact
Copper-tungsten contacts are frequently used in high power circuit breakers and contactors in air, oil, SF/sub 6/, or vacuum. Arc interruption and anti-welding properties are important design parameters. In this study, we examined the effects of tungsten particle size on reignition and weld resistance in air. Oxidation and mechanical properties are also determined to find the optimum contact properties for arc erosion under thermal and mechanical stresses. Static gap arc erosion is used to supplement observations in a dynamic weld test. This avoided device mechanical variables that affect contact erosion.
Calculation of and Errors in the Susceptibility
The measurement of the susceptibility requires three measurements, two of which have to be performed with a substance of known susceptibility. The difference of these last two measurements furnishes the proportionality constant of the apparatus, always employing the same volume, while the difference with the unknown substance gives the required susceptibility.