Mutual inductance of two coils COMSOL 6.0 AC/DC electromagnetics
 

Hi,

I use the expression mf.L_2_1 for obtaining the M between two coils in a 3D model, but when click "evaluate", appears next error:

Undefined variable. - Variable: mf.L_2_1 - Global scope Failed to evaluate expression. - Expression: mf.L_2_1 - Feature: Global Evaluation 1

Do you know why?

Thnks in advance!