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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'''
| + | 75181 Pforzheim / Germany<br> |
− | : <math>R_e = \rho/2a</math>
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− | (Single spot contact according to Holm; circular touching spot between clean
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− | contact surfaces)
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− | : <math>R_e = \rho/2Na</math>
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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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− | : <math>R_e = \rho/2 x \sum a_i + 3 \pi \rho /32N^2 x \sum \sum (s_ij) i \neq j</math>
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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'''
| + | Phone +49 (0) 7231 602-0<br> |
− | : <math>R_K = R_e + R_f</math>
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− | *'''Path resistance'''
| + | Fax +49 (0) 7231 602-398<br> |
− | : <math>cR_d = R_b + R_K</math>
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− | *'''Contact resistance and contact force'''
| + | Mail: info@doduco.net<br> |
− | : <math>R_K = 280\rho \sqrt[3]{E (F_K \cdot r)} </math> | |
− | (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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− | : <math>R_K = 9000 \rho \sqrt{ H/ F_K}</math>
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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)
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− | : <math>F_A \approx 0,8 xl^2</math>
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− | (Rule of thumb with F<sub>A</sub> in N and l in kA)
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− | *'''Contact voltage and max. contact temperature'''
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− | : <math>T_kmax \approx 3200 U_K</math>
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− | *'''Contact resistance at higher contact forces (according to Babikow)'''
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− | : <math>R_K = cF_k^{-m}</math>
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− | For F<sub>K</sub> between 10 and 200 N<br/>
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− | c = material dependent proportionality factor<br/>
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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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