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

*'''Constriction resistance''' Re : <math>R_e = D\rho/2a</math>

Re : <math>R_e = D\rho/2Na</math>

Re : <math>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>

als bild?  *'''Contact resistance''' : <br /math>RK R_K = Re R_e + RfR_f</math>

*'''Path resistance''' : <br /math>Rd R_d = Rb R_b + RKR_K</math>

R : <math>R_K = 280D ³ 280\rho \sqrt[3]{E(F · F_K \cdot r) K K} </math>

deformation of the contact material; F _k < 1 N for typical contact materials) kRK : <math>R_K = 9000 D \rho \sqrt{ H/ FKF_K}</math>

deformation of the contact material; F _k > 5 N for typical contact materials)

*'''Dynamic Contact voltage and max. contact separationtemperature''' (without considering magnetic fields caused by the current path): <math>T_kmax \approx 3200 U_K</math>

FA 0,8 x I²*'''Contact resistance at higher contact forces (according to Babikow)''' : <math>R_K = cF_k^{-m}</math>(Rule of thumb with For F in _K between 10 and 200 N and I in kA)<br/>c = material dependent proportionality factor<br/>m = shape dependent exponent of the contact force

*'''Contact resistance at higher contact forces {| class="twocolortable scalable" style="text-align: left; font-size: 12px; width:45%;"|-!Material combination !c|-|Copper - Copper |(0.08 bis 0.14) x 10^-3|-|Aluminum - Aluminum|(according to Babikow3 bis 6,7)'''x 10^-3|-|Brass - Brass |0.67 x 10^-3R = cF |-|Steel – Silver|0.06 x 10^-3|-|Steel – Copper|3.1 x 10^-3|-m K KFor F between |Steel – Brass|3.0 x 10 and 200 N K^-3|}c {| class="twocolortable scalable" style= material dependent proportionality factor"text-align: left; font-size: 12px; width:45%; "|-!Contact shapes !m |-|Flat – Flat |1|-|Pyramid – Flat|0.5|-|Sphere – Flat |0.6|-|Sphere – Sphere|0.5|-|Multi-strand brush - Flat|1|-|Current bar (Busbar) contact|0.5 - 0.7|}<div class= shape dependent exponent of the contact force"clear"></div>

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