Learning Center Simulation: Modeling a Coil Connected to a Circuit

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Hello,

I am following along to the COMSOL Learning Center video titled Modeling of a Coil Connected to a Circuit and have come across an issue. I am able to follow along seamlessly with the tutorial until 41:25, where the instructor changes the core to instead be a hollow solid instead of just being off to the side. When it's done in the video, COMSOL immediately understands what all the domains should be assigned to and computes the solution. But in my file (COMSOL 6.2.0.339) domain 5, which is the air inside the hollow core, can not have any domains applied to it as it is "Not applicable." Magnetic insulation is applied to both the coils and the core by default and I get a trivial solution. Is there something that I'm doing wrong when trying to follow along?

I attached both a .mph file from just before the hollow core is added, and a .mph file with the trivial solution (this one has Issue appended to the title).



1 Reply Last Post 10.06.2025, 14:57 MESZ
Walter Frei COMSOL Employee

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Posted: 15 hours ago 10.06.2025, 14:57 MESZ

Hello Adolfo,

Within your model, go to the Component 1 > Magnetic Fields interface settings: Domain Selection, and set the "Selection:" to "All Domains". Once that's done, domain #5 (the hollow within the 2D axisymmetric core) will be included.

Happy Modeling!

Hello Adolfo, Within your model, go to the Component 1 > Magnetic Fields interface settings: Domain Selection, and set the "Selection:" to "All Domains". Once that's done, domain #5 (the hollow within the 2D axisymmetric core) will be included. Happy Modeling!

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