EM FAQ: How does Maxwell compute the AC resistance?
The AC resistance is calculated R=P/(I^2), with P the integral of ohmic loss on the concerned conductor. You can check it by comparing the Matrix result and build the resistance from the calculator as the equation above.
The formula via the fields calculator is: R=Loss(conductor1)/Current(Conductor1)^2
To implement it the steps are the following:
Input -> Quantity -> Ohmic Loss
Geometry -> Volume (or Surface) -> (select the object)
Scalar -> Integral
Input -> Number -> Scalar ->(introduce the current)
Input -> Number -> Scalar ->(introduce the current)
General ->
* General -> /
The matrix does: R=Loss(All parts from current in conductor1)/Current(Conductor1)^2