===<!--6.4.2-->Contact Physics – Formulas==={| *|'''Constriction resistanceEditor''' : $R_e = \rho/2a$(Single spot contact according to Holm; circular touching spot between cleancontact surfaces): $R_e = \rho/2Na$(Multi-spot contact according to Holm without influence between the Nindividual spots): $R_e = \rho/2 x \sum a_i + 3 \pi \rho /32N^2 x \sum \sum (s_ij) i \neq j$(Multi-spot contact according to Greenwood considering the influence betweenthe spots) *'''Contact resistance''': $R_K = R_e + R_f$ *'''Path resistance''' : $R_d = R_b + R_K$ *'''Contact resistance and contact force''': $R_K = 280\rho \sqrt[3]{E (F_K \cdot r)} $ (According to Holm model for film-free spherical contact surfaces with plasticdeformation of the contact material; F|DODUCO Holding GmbH<subbr>kIm Altgefäll 12</subbr> < 1 N for typical contact materials): $R_K = 9000 \rho \sqrt{ H75181 Pforzheim / F_K}$(According to Holm model for film-free spherical contact surfaces with plasticdeformation of the contact material; FGermany<sub>k</sub> br> 5 N for typical contact materials) *'''Dynamic contact separation''' Phone +49 (without considering magnetic fields caused by the current path0) : $F_A \approx 7231 602-0,8 xl^2$(Rule of thumb with F<subbr>A</sub> in N and l in kA) *'''Contact voltage and max. contact temperature''': $T_kmax \approx 3200 U_K$ *'''Contact resistance at higher contact forces Fax +49 (according to Babikow0)''' : $R_K = cF_k^{7231 602-m}$For F<sub>K</sub> between 10 and 200 N398<br/>c = material dependent proportionality factorMail: info@doduco.net<br/>m = shape dependent exponent of the contact force {| class="twocolortable scalable" style="text-align: left; font-size: 12px; width:45%;"
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!Material combination |'''Managing Directors''':!c|Dr. Hans-Joachim Dittloff (Vorsitzender)<br>Dr. Franz Kaspar<br>Hajo Kufahl<br>
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|Copper - Copper '''Registration''':|(0.08 bis 0.14) x 10<sup>-3</sup>HRB 710592 AG Mannheim
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|Aluminum - Aluminum'''Consulting and Realisation''':|Steinbeis - Transferzentrum Unternehmensentwicklung an der Hochschule Pforzheim (3 bis 6,7SZUE) x 10<supbr>Blücherstraße 32 <br>-375177 Pforzheim <br>https://www.szue.de/sup>
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|Brass '''Revision and German version''':|Christian Teitscheid - Brass Teitscheid Freelance IT<br>Barbarastraße 22 <br>|0.67 x 1047495 Rheinberg <supbr>http://www.teitscheid-3<freelance.de/sup>
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|Steel – Silver
|0.06 x 10<sup>-3</sup>
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|Steel – Copper
|3.1 x 10<sup>-3</sup>
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|Steel – Brass
|3.0 x 10<sup>-3</sup>
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!Contact shapes
!m
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|Flat – Flat
|1
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|Pyramid – Flat
|0.5
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|Sphere – Flat
|0.6
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|Sphere – Sphere
|0.5
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|Multi-strand brush - Flat
|1
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|Current bar (Busbar) contact
|0.5 - 0.7
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==References==
[[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
[[de:Formeln_aus_der_Kontaktphysik]]
