PaulaSilva72
Electrical
I’m modeling a permanent magnet machine using a commercial FEA software. I had found some unexpected values for the magnetic field H related with magnetic flux density B, so I tried to track how the software deals with it using simple examples.
When I calculate the magnetic field H and the magnetic flux density B due to a straight wire carrying a current, the results are coherent with theory, given the same H independent of the medium where the wire is located and different values for B, such that B=absolute permeability*H.
In the case of a solenoid, I found results that I do not understand: consider a long solenoid, with a small cross section area, such that in the center of it we may consider H=NI/h (h is the height of the solenoid, N the number of turns, I current); solving FEA when the solenoid has no magnetic material in the interior (case1), results for B and H are coherent with the expected ones, but with a linearized soft ferromagnetic material inside the solenoid (case2), I found that the results for H are no longer equal to NI/h. H should be the same independent of the solenoid core material.
I believe I’m failing somewhere, but I cannot figure out what.
Thanking in advance any consideration about the results in attach.
When I calculate the magnetic field H and the magnetic flux density B due to a straight wire carrying a current, the results are coherent with theory, given the same H independent of the medium where the wire is located and different values for B, such that B=absolute permeability*H.
In the case of a solenoid, I found results that I do not understand: consider a long solenoid, with a small cross section area, such that in the center of it we may consider H=NI/h (h is the height of the solenoid, N the number of turns, I current); solving FEA when the solenoid has no magnetic material in the interior (case1), results for B and H are coherent with the expected ones, but with a linearized soft ferromagnetic material inside the solenoid (case2), I found that the results for H are no longer equal to NI/h. H should be the same independent of the solenoid core material.
I believe I’m failing somewhere, but I cannot figure out what.
Thanking in advance any consideration about the results in attach.