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Problem with material properties and conductivity
Posted Jan 28, 2010, 8:54 a.m. EST 3 Replies
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Hello everyone,
Still working on my 2d generator, I tried to set copper conductors with an external current density, Jez, depending on the time. But I figured that if the value of sigma (electric conductivity) is not equal to zero, the calculated field "almost" doesn't move with the rotor. If the conductivity is set to zero, no problem.
I attach one case with a current density of zero and a nonzero conductivity (where the magnetic flux density almost doesn't move), and one with nonzero current density and zero conductivity.
Some help would be great!
Ronan
Still working on my 2d generator, I tried to set copper conductors with an external current density, Jez, depending on the time. But I figured that if the value of sigma (electric conductivity) is not equal to zero, the calculated field "almost" doesn't move with the rotor. If the conductivity is set to zero, no problem.
I attach one case with a current density of zero and a nonzero conductivity (where the magnetic flux density almost doesn't move), and one with nonzero current density and zero conductivity.
Some help would be great!
Ronan
3 Replies Last Post Feb 8, 2010, 11:56 a.m. EST
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Posted:
1 decade ago
No answer?
I've read something on this forum about the fact that one shouldn't set a non-zero conductivity in such a case. But I couldn't anderstand the reason..
I still would be very thankful to any help
Ronan
I've read something on this forum about the fact that one shouldn't set a non-zero conductivity in such a case. But I couldn't anderstand the reason..
I still would be very thankful to any help
Ronan
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Posted:
1 decade ago
Hi
Perhaps you can find some explanations if you look at the current density plots of "normJ_emqa".
To enhace the current plot in (sigma <>0) case try to plot "log(normJ_emqa)"
For me this explains the effect on the field, but then why such current density differences.
There are a couple of discussion around on the effect of bulk coils or simulated wounded coils, could be an issue for you too
Have you checked that the total current is really there, and that you do not have any unexpected impedance / skin effects going on ?
Good luck
Ivar
Perhaps you can find some explanations if you look at the current density plots of "normJ_emqa".
To enhace the current plot in (sigma <>0) case try to plot "log(normJ_emqa)"
For me this explains the effect on the field, but then why such current density differences.
There are a couple of discussion around on the effect of bulk coils or simulated wounded coils, could be an issue for you too
Have you checked that the total current is really there, and that you do not have any unexpected impedance / skin effects going on ?
Good luck
Ivar
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Posted:
1 decade ago
Hi,
Thanks for answering.
Unfortunately I couldn't find discussions on this forum that help me.
I also don't understand the high value of the induced current (until 1e6 !), with magnets of remanence 1 Tesla.
In the meanwhile I tried a different approach, following the one in "Generator Sector Dynamic". But I have now a completely different problem. I'll create a new topic to ask about it.
Cordially
Ronan
Thanks for answering.
Unfortunately I couldn't find discussions on this forum that help me.
I also don't understand the high value of the induced current (until 1e6 !), with magnets of remanence 1 Tesla.
In the meanwhile I tried a different approach, following the one in "Generator Sector Dynamic". But I have now a completely different problem. I'll create a new topic to ask about it.
Cordially
Ronan