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modeling a 3d electromagnet in a stationary study

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Hey i am having som trouble.

it is giving me this error:
and i can't figure out why!
i tried to use and modify the "Multi_Turn Coil Winding around a Rectangular Ferromagnet cleared.mph" to help me make it. i modified the size and use it in a stationary rather than frequency domain so it fits my needs. but i can't seem to compute it.

im new in comsol, so it might just be a brain fart.

the error i get is:
Division by zero.
- Function: /
Failed to evaluate variable.
- Variable: comp1.mf.Jey
- Defined as: ((comp1.mf.ICoil_1*comp1.mf.mtcd1.eCoily)*N)/comp1.mf.mtcd1.area
Failed to evaluate variable.
- Variable: comp1.mf.Jy
- Defined as: comp1.mf.Jiy+comp1.mf.Jey
Failed to evaluate expression.
- Expression: d((comp1.mf.d*(-comp1.mf.Hx*comp1.mf.testcurlAx-comp1.mf.Hy*comp1.mf.testcurlAy-comp1.mf.Hz*comp1.mf.testcurlAz+comp1.mf.Jx*test(comp1.mf.Adepx)+comp1.mf.Jy*test(comp1.mf.Adepy)+comp1.mf.Jz*test(comp1.mf.Adepz)))*(dvol),{test@24})

the file is to large to upload it here. so i put it in my google drive at:
drive.google.com/open?id=0B52pVuxc2-oFU1FDNnZXV19aTms

thank you in advance.

6 Replies Last Post 2017年5月3日 GMT-4 02:49
Morten Siwertsen COMSOL Employee

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Posted: 8 years ago 2016年5月17日 GMT-4 07:34
Hi Christian,

When using a "Multi-Turn Coil" feature you need to add a "Coil Geometry Analysis" study. You can either add a new study or simply add a new study step to your current study 1 sequence: Right-click "Study 1" and choose "Study steps" > "Other" > "Coil Geometry Analysis".
Make sure the Coil Geometry Analysis step is step 1 in the study sequence - you can drag it up using your mouse. Step 2 should be the Stationary step.
Now you should be able to solve it.
Running the model a warning is shown that domain 6 and 9 does not contain a mesh, so either remove those domains from the "Magnetic Field" physics interface or add a mesh to them

Best regards,
Morten
Hi Christian, When using a "Multi-Turn Coil" feature you need to add a "Coil Geometry Analysis" study. You can either add a new study or simply add a new study step to your current study 1 sequence: Right-click "Study 1" and choose "Study steps" > "Other" > "Coil Geometry Analysis". Make sure the Coil Geometry Analysis step is step 1 in the study sequence - you can drag it up using your mouse. Step 2 should be the Stationary step. Now you should be able to solve it. Running the model a warning is shown that domain 6 and 9 does not contain a mesh, so either remove those domains from the "Magnetic Field" physics interface or add a mesh to them Best regards, Morten

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Posted: 8 years ago 2016年5月17日 GMT-4 08:21
Thanks a lot, Morten, that was just what i needed, now i just need to figure out how to make a 3d plot with the Air "hidden".

but that is a far smaller problem.

thanks again
Thanks a lot, Morten, that was just what i needed, now i just need to figure out how to make a 3d plot with the Air "hidden". but that is a far smaller problem. thanks again

Morten Siwertsen COMSOL Employee

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Posted: 8 years ago 2016年5月17日 GMT-4 08:56
If you right-click the data set ("Results" > "Data Sets" > "Study...") and choose "Selection", you can tell COMSOL which geometric entities should be visualized when using that data set.
Hint: Right-click the Data Set and select Duplicate. Now you can choose which data set to viasualize in the plot groups. More information is available in the "Postprocessing & Visualization Handbook, part 1 & 2" that is available at: www.comsol.dk/resources (look under "Product literature")

Hope it helps.
Morten
If you right-click the data set ("Results" > "Data Sets" > "Study...") and choose "Selection", you can tell COMSOL which geometric entities should be visualized when using that data set. Hint: Right-click the Data Set and select Duplicate. Now you can choose which data set to viasualize in the plot groups. More information is available in the "Postprocessing & Visualization Handbook, part 1 & 2" that is available at: https://www.comsol.dk/resources (look under "Product literature") Hope it helps. Morten

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Posted: 8 years ago 2016年5月17日 GMT-4 09:14
thanks a million!

problem solved, so far.
thanks a million! problem solved, so far.

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Posted: 7 years ago 2017年5月2日 GMT-4 11:53
I have a single coil; how do I choose stationary-frequency? I don't see an option here for my 3D model...
I have a single coil; how do I choose stationary-frequency? I don't see an option here for my 3D model...

Morten Siwertsen COMSOL Employee

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Posted: 7 years ago 2017年5月3日 GMT-4 02:49
Hi Malavika,

This can happen if you complete the initial Model Wizard without choosing a study. To add a study to your Model Builder, just right-click the root (top of the Model Builder), and select "add study". Select your study from the "add study"-window, and you should be ready to go.

Hope it helps. Otherwise feel free to contact technical support: www.comsol.com/support

Morten

Hi Malavika, This can happen if you complete the initial Model Wizard without choosing a study. To add a study to your Model Builder, just right-click the root (top of the Model Builder), and select "add study". Select your study from the "add study"-window, and you should be ready to go. Hope it helps. Otherwise feel free to contact technical support: www.comsol.com/support Morten

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