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− | ===6.4.2 Contact Physics – Formulas===
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| + | |'''Editor''': |
| + | |DODUCO Holding GmbH<br> |
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| + | Im Altgefäll 12<br> |
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− | *'''Constriction resistance''' <br />R<sub>e</sub> = \rho/2a
| + | 75181 Pforzheim / Germany<br> |
− | (Single spot contact according to Holm; circular touching spot between clean
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− | contact surfaces)
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− | R<sub>e</sub> = \rho/2Na
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− | (Multi-spot contact according to Holm without influence between the N
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− | individual spots)
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− | R<sub>e</sub> = \rho/2 x \sum a<sub>i</sub> + 3 \pi \rho/32N² x \sum \sum (s<sub>ij</sub>) i \neq j
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− | (Multi-spot contact according to Greenwood considering the influence between
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− | the spots)
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− | *'''Contact resistance''' <br />R<sub>K</sub> = R<sub>e</sub> + R<sub>f</sub>
| + | Phone +49 (0) 7231 602-0<br> |
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− | *'''Path resistance''' <br />R<sub>d</sub> = R<sub>b</sub> + R<sub>K</sub>
| + | Fax +49 (0) 7231 602-398<br> |
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− | *'''Contact resistance and contact force''' <br />R<sub>K</sub> = 280D ³ E(F · r) K
| + | Mail: info@doduco.net<br> |
− | (According to Holm model for film-free spherical contact surfaces with plastic
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− | deformation of the contact material; F<sub>k</sub> < 1 N for typical contact materials)
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− | R<sub>K</sub> = 9000 D H/ FK
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− | (According to Holm model for film-free spherical contact surfaces with plastic
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− | deformation of the contact material; F<sub>k</sub> > 5 N for typical contact materials)
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− | *'''Dynamic contact separation''' (without considering magnetic fields caused by the current path) <br />F<sub>A</sub> 0,8 x I<sup>2</sup>(Rule of thumb with F<sub>A</sub> in N and I in kA)
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− | *'''Contact voltage and max. contact temperature''' <br />T<sub>kmax</sub> 3200 U<sub>K</sub>
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− | *'''Contact resistance at higher contact forces (according to Babikow)''' <br />R<sub>K</sub> = cF -m K
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− | For F<sub>K</sub> between 10 and 200 N
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− | c = material dependent proportionality factor
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− | m = shape dependent exponent of the contact force
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− | ==References==
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− | [[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
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