Difference between revisions of "Contact Physics – Formulas"
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*'''Path resistance''' cR<sub>d</sub> = R<sub>b</sub> + R<sub>K</sub> | *'''Path resistance''' cR<sub>d</sub> = R<sub>b</sub> + R<sub>K</sub> | ||
| − | *'''Contact resistance and contact force''' <math>R_K = | + | *'''Contact resistance and contact force''' <math>R_K = 280\rho^3 \sqrt[E]{F_K · r} </math> |
(According to Holm model for film-free spherical contact surfaces with plastic | (According to Holm model for film-free spherical contact surfaces with plastic | ||
deformation of the contact material; F<sub>k</sub> < 1 N for typical contact materials) | deformation of the contact material; F<sub>k</sub> < 1 N for typical contact materials) | ||
Revision as of 18:28, 26 March 2014
6.4.2 Contact Physics – Formulas
- Constriction resistance
(Single spot contact according to Holm; circular touching spot between clean
contact surfaces)
(Multi-spot contact according to Holm without influence between the N
individual spots)
(Multi-spot contact according to Greenwood considering the influence between
the spots)
- Contact resistance RK = Re + Rf
- Path resistance cRd = Rb + RK
- Contact resistance and contact force
![R_K = 280\rho^3 \sqrt[E]{F_K · r}](/matheasy/15d7e7a453547e4938951b977d26959e.svg)
(According to Holm model for film-free spherical contact surfaces with plastic
deformation of the contact material; Fk < 1 N for typical contact materials)
(According to Holm model for film-free spherical contact surfaces with plastic
deformation of the contact material; Fk > 5 N for typical contact materials)
- Dynamic contact separation (without considering magnetic fields caused by the current path)
FA 0,8 x I2(Rule of thumb with FA in N and I in kA)
- Contact voltage and max. contact temperature
Tkmax 3200 UK
- Contact resistance at higher contact forces (according to Babikow)
RK = cF -m K
For FK between 10 and 200 N c = material dependent proportionality factor m = shape dependent exponent of the contact force
