magnetic field in 3D: setting coil currents and turns

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emmy.t
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magnetic field in 3D: setting coil currents and turns

Post by emmy.t »

Hi,

I'm working on analyzing the magnetic field around coils in 3D, and leaning from manuals and others works.
I want to specify the coil current and the number of turns to each coils, but I'm wondering how to set these. (I'm not familiar with non-gui also)

First of all, is that possible? or should I set current density and magnetic flux density?
if i need to set the current densities, what is the difference of setting the current density as a boundary condition, component (or solver if it's a single coil), and body force?
Also, I saw some works using keywords like "current in" and "current out", and set potentials as a boundary condition.

what are the differences and how should I choose?

Thanks in advance.
kevinarden
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Re: magnetic field in 3D: setting coil currents and turns

Post by kevinarden »

https://github.com/ElmerCSC/elmerfem/tr ... /fem/tests

several test cases here for coil currents.
raback
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Re: magnetic field in 3D: setting coil currents and turns

Post by raback »

Hi

Typically if you have coils you have hierarchical simulation such that you 1st resolve the coil currents and then the magnetic fields.

If you can write down the analytical formula for the coil current then you don't need any computation. Typically this would involve setting "Current Density i", i=1,2,3 in the volume involving some trigonometric functions in LUA, MATC or Fortran.

If your geometry is complex you need to solve it. The StatCurrentSolver basically does this and then needs the "Current Density" (or potential) as BC only. The limitation of this solver is that it cannot deal with closed loops. For this purpose the CoilSolver was coined. It has some special strategies for coils.

Finally you would AV solver to compute the magnetic field whatever the way you define the current density. There are tens of test cases for these different solvers. Also you will find long discussions in the forum on solving such systems. Most often these are not defined by the GUI.

-Peter
emmy.t
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Re: magnetic field in 3D: setting coil currents and turns

Post by emmy.t »

Kevin,
thanks for sharing. I'm going to take a look and try again.

Peter,
thank you, I understand general flow. As I thought it's difficult to solve in GUI.
granzer
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Re: magnetic field in 3D: setting coil currents and turns

Post by granzer »

To model the coil, where to input the number of turns and the dia of the coil windings....Or is the only way to model the coil is to actually make the CAD model with the given number of turns (say 5000 turns, 1mm dia, and coil length of 20mm)
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