===6.4.2 Contact Physics – Formulas==={| |'''Editor''':|DODUCO Holding GmbH<br> Im Altgefäll 12<br>
*'''Constriction resistance''' 75181 Pforzheim / Germany<br />R<sub>e</sub> = D/2a(Single spot contact according to Holm; circular touching spot between cleancontact surfaces)R<sub>e</sub> = D/2Na(Multi-spot contact according to Holm without influence between the Nindividual spots)R<sub>e</sub> = D/2 x E ai + 3B D/32N² x E E (sij) i = j(Multi-spot contact according to Greenwood considering the influence betweenthe spots)
als bild?Phone +49 (0) 7231 602-0<br>
*'''Contact resistance''' Fax +49 (0) 7231 602-398<br />R<sub>K</sub> = R<sub>e</sub> + R<sub>f</sub>
*'''Path resistance''' <br />R<sub>d</sub> = R<sub>b</sub> + R<sub>K</sub> *'''Contact resistance and contact force''' <br />R<sub>K</sub> = 280D ³ E(F · r) K (According to Holm model for film-free spherical contact surfaces with plasticdeformation of the contact material; F<sub>k</sub> < 1 N for typical contact materials)R<sub>K</sub> = 9000 D H/ FK(According to Holm model for film-free spherical contact surfaces with plasticdeformation of the contact material; F<sub>k</sub> > 5 N for typical contact materials) *'''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) *'''Contact voltage and maxMail: info@doduco. contact temperature''' net<br />T<sub>kmax</sub> 3200 U<sub>K</sub> *'''Contact resistance at higher contact forces (according to Babikow)''' <br />R<sub>K</sub> = cF -m KFor F<sub>K</sub> between 10 and 200 Nc = material dependent proportionality factorm = shape dependent exponent of the contact force ==References==[[Application Tables and Guidance Data for the Use of Electrical Contacts#References|References]]
