## WhitneyAV 3D coupled current emag of a coil

Elmer cases by the users for the users
danielgboyle
Posts: 6
Joined: 24 Oct 2011, 20:26
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### WhitneyAV 3D coupled current emag of a coil

This shows the elmer analysis of a coil embedded in a square volume of air with the following dimensions:

I=12.5 amps
L=62.5 mm
coil DIA=60 mm
wire DIA=12 mm
Number of turns=2.5

See attached images also. Results of Bz on axis are accurate as compared to other FEA codes and formula. Unfortunately I could not upload the vtk output or the elmergrid output files as they exceeded the 2 Mb limit but if you run this example then all of these will be generated.
Attachments
WhitneyAV_3d_emag.7z
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pics.zip
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madstamm
Posts: 37
Joined: 07 Apr 2010, 09:56

### Re: WhitneyAV 3D coupled current emag of a coil

Thank you Daniel!

I made liberal use of your sif file in the example i just posted here:
viewtopic.php?f=3&t=2053

...spend a long time last year trying to get acquainted with Elmer, and playing with the Whitney solver - while Juha was working out the bugs

It looks like things are on track to becoming useful for E-M problems.

Mike
madstamm
Posts: 37
Joined: 07 Apr 2010, 09:56

### Re: WhitneyAV 3D coupled current emag of a coil

Hi Daniel,

I do have a question regarding your example:

I noticed in the sif file that you specify the current in two ways:
1) using "Current Control = Real 12.5 , as well as
2) specifying the potentials at the wire ends, "Potential = 0.001" and "Potential = 0.0" - this, together with the resistance of the coil, also gives the current...

Using (2):
approximating the length of your coil wire to 3 turns, and using length=pi()*D*3, you get about 0.6m of "copper wire".
approximating the 12mm diam to be AWG0000, you get about 0.00008Ohm resistance...
0.001V/0.00008Ohm = 1.25A...

Have you tried turning off the "Current Control" to see if you get the same result?

Mike
danielgboyle
Posts: 6
Joined: 24 Oct 2011, 20:26
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### Re: WhitneyAV 3D coupled current emag of a coil

Mike -
Apologies for not replying sooner. I didn't think anyone would be interested in my post. I will try what you suggest and reply.
Regards,
Dan
jtapas3761
Posts: 8
Joined: 16 Jul 2018, 10:17
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### Re: WhitneyAV 3D coupled current emag of a coil

Hi Daniel,

I have recently started using Elmer for generating the magnetic field around a current carrying coil. I was using your example as a reference to understand the working. I am able to run your files as you mentioned in your post to generate the results. However, the Elmer software crashes every time after 150000 iterations. Can you tell me why this might be happening? Thanks!
raback
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### Re: WhitneyAV 3D coupled current emag of a coil

Hi

Sometimes I remember that there was a problem with the very long runs (and the convergence plotter) when using GUI. Are you running the case using GUI? If yes, perhaps you could try using command line.

-Peter
mzenker
Posts: 1997
Joined: 07 Dec 2009, 11:49
Location: Germany

### Re: WhitneyAV 3D coupled current emag of a coil

Hi,

I also rember having had this kind of problem with long runs in the GUI. At the time it seemed that the buffer of the log window has some kind of size limitation.

Matthias
jtapas3761
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Joined: 16 Jul 2018, 10:17
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### Re: WhitneyAV 3D coupled current emag of a coil

raback wrote: 10 Sep 2018, 16:40 Hi

Sometimes I remember that there was a problem with the very long runs (and the convergence plotter) when using GUI. Are you running the case using GUI? If yes, perhaps you could try using command line.

-Peter
Hi raback

I am using elmer 8.0 on windows 7 and as you pointed out I was using GUI for running the example. But when calling elmergrid or elmersolver from a cmd window, widows reported that they were not recognised as an internal or external command. Do you have any idea why ?
mzenker
Posts: 1997
Joined: 07 Dec 2009, 11:49
Location: Germany

### Re: WhitneyAV 3D coupled current emag of a coil

Hi,

you need to have the bin directory inside the Elmer installation directory in your Path.

HTH,
Matthias
jtapas3761
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Joined: 16 Jul 2018, 10:17
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### Re: WhitneyAV 3D coupled current emag of a coil

Hi Mzenker and Raback,

Thanks for your help. The solver works fine using the cmd lines now. Just facing a new problem as shown below. Has anyone gone through the same???
Attachments
hgf.PNG (23.99 KiB) Viewed 3891 times