Changes

===<!--6.4.2 -->Contact Physics – Formulas===

*'''Constriction resistance''' : <br math>R_e = \rho/>R<sub>e2a</submath> = D/2a

R: <submath>eR_e = \rho/2Na</submath> = D/2Na

R: <sub>e</submath> R_e = D\rho/2 x E ai \sum a_i + 3B D3 \pi \rho /32N² 32N^2 x E E \sum \sum (sijs_ij) i = \neq j</math>

*'''Contact Path resistance''' : <br />R<sub>K</submath> R_d = R_e R_b + R<sub>fR_K</submath>

*'''Path resistance''' <br />R_d = R_b + R_K *'''Contact resistance and contact force''' : <br />R<sub>K</submath> R_K = 280D ³ 280\rho \sqrt[3]{E(F · F_K \cdot r) K } </math>

R: <sub>K</submath> R_K = 9000 D \rho \sqrt{ H/ FKF_K}</math>

*'''Dynamic contact separation''' (without considering magnetic fields caused by the current path) : <br />F<sub>A</submath> F_A \approx 0,8 x I<sup>xl^2</supmath>(Rule of thumb with F_A in N and I l in kA)

*'''Contact voltage and max. contact temperature''' : <br />T<sub>kmax</submath> T_kmax \approx 3200 U<sub>KU_K</submath>

*'''Contact resistance at higher contact forces (according to Babikow)''' : <math>R_K = cF_k^{-m}<br /math>RFor F_K = cF -m KFor F between 10 and 200 N K<br/>c = material dependent proportionality factor<br/>

[[Application Tables and Guidance Guideline Data for the Use of Electrical ContactsContact Design#References|References]] [[de:Formeln_aus_der_Kontaktphysik]]