Discussion Forum

Hi

there are a few points in your model, among other you define a GND and a Voltage source internal boundary, but how can you write the Maxwell equations in a closed volume with suddenly you have an appearing/dissapearing current source ? and no loop ?

the best is probably to loop your coil all the way to the external boundary and then use the external surface/boundary as current closing loop.

Next is rather a remarque, the magnetic and electric field will tend to a spherical symmetry around your model, So I would have used a sphere for the air instead of a cube, as then your B field loops around nices without any "corner effects"


fnal comment, try to avoid right angles shapes for the domins, as a right angle corner is a singularity for MEF A part, you have rounded somecorners I see but not all, this is also of less importance, except if you are studying the filed in details

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Good luck
Ivar

Hi

there are a few points in your model, among other you define a GND and a Voltage source internal boundary, but how can you write the Maxwell equations in a closed volume with suddenly you have an appearing/dissapearing current source ? and no loop ?

the best is probably to loop your coil all the way to the external boundary and then use the external surface/boundary as current closing loop.

Next is rather a remarque, the magnetic and electric field will tend to a spherical symmetry around your model, So I would have used a sphere for the air instead of a cube, as then your B field loops around nices without any "corner effects"


fnal comment, try to avoid right angles shapes for the domins, as a right angle corner is a singularity for MEF A part, you have rounded somecorners I see but not all, this is also of less importance, except if you are studying the filed in details

--
Good luck
Ivar

Thank you Ivar,
when we can get married? :D
Seriously your help saved my life, now i can simulate the inductor, i have rounded the corners, i can now see the B field...the real problem is the too big mesh, i need 26 turns in my inductor and with simulator i obtained "out of memory" with more of 3 turns!!!!
do you think is a good idea to work in 2D?I decided to draw the inductor as in the attached figure. But how to bring my results in 3d?


I have also used a BH curve for ferrite core material...now i am trying to find the saturation current (at least with 3 turns)

Hi

if you can work in 2D (i.e. a "simple" 2d-axi) its always much better. For multiturn coils you have the new BC's in V4.1, really nice, ut you must read carefully the doc, and look at the equations, these are subtil BC's adding new dependent variables to solve localy for V. But once you master them they will make life far easier for you

Concerning marriage, I'm already far engaged, with grown up kids, so I'm certainly not interesting, far better as physics teacher on the web ;)

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Good luck
Ivar

Hi Ivar,
i have only the 4.0a! It's the same? Or i need the 4.1?

Hi

v4.0 was the first issue of the new release, as with any software the "improvement curve" is strongest at the beginning ofa new version, that is why I believe one should never really work with a ".0" version, just use it to prepare onself to the new interface, and switch asap to the next release, today it's 4.1 + patch, and soon (a few months) I blieve the 4.2 will arive. With COMSOL as any with other heavy tool, it is really also worth to keep the maintenance, and I find their preices correct for the tool quality

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Good luck
Ivar