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Inductance of helical core with and without iron core
Posted Apr 5, 2016, 1:06 a.m. EDT Low-Frequency Electromagnetics Version 5.2 4 Replies
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Hi all,
I'm trying to create an inductor at a given uH, using the mef-module and applying voltage at a terminal in one end of the helix and applying ground at the opposite end.
Using the built-in value I can retrieve the inductance: mef.L11.
Let'a say that for a small mm-sized helix with 10 turns and air core I get 0.03 uH.
I would then expect to have a much higher inductance when placing a sylindrical iron core in the center of the helix, but the result is still the same (i have tried with and without applying the ground boundery to the iron core).
How to get COMSOL to "use" the iron core to boost the indutance?
I also wonder why I get "not applicable" on the helix end-bounderies when assigning ground and terminal when the entire model is inside a sphere of air.
--
:)
I'm trying to create an inductor at a given uH, using the mef-module and applying voltage at a terminal in one end of the helix and applying ground at the opposite end.
Using the built-in value I can retrieve the inductance: mef.L11.
Let'a say that for a small mm-sized helix with 10 turns and air core I get 0.03 uH.
I would then expect to have a much higher inductance when placing a sylindrical iron core in the center of the helix, but the result is still the same (i have tried with and without applying the ground boundery to the iron core).
How to get COMSOL to "use" the iron core to boost the indutance?
I also wonder why I get "not applicable" on the helix end-bounderies when assigning ground and terminal when the entire model is inside a sphere of air.
--
:)
4 Replies Last Post Apr 7, 2016, 3:09 a.m. EDT
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Posted:
8 years ago
Hello,
Extremities of the your helix coil must be external boundaries of the simulation domain
Best regards
Julien
Extremities of the your helix coil must be external boundaries of the simulation domain
Best regards
Julien
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Posted:
8 years ago
Thank you, Julien.
After figuring out how to "extend" the helix ends, I was eventually able to connect it to the domain boundery and get some flux flowing :)
My next question:
I have two methods to retrieve the coil inductance:
1) Using built-in variable mef.LCoil_1 = 452.17 uH
2) Using the energy method: abs((mef.intWm*2)/(mef.ICoil_1^2)) = 226.09 uH
Why does the latter return an indutance which is exactly 50% of the built-in inductance calculation?
--
:)
After figuring out how to "extend" the helix ends, I was eventually able to connect it to the domain boundery and get some flux flowing :)
My next question:
I have two methods to retrieve the coil inductance:
1) Using built-in variable mef.LCoil_1 = 452.17 uH
2) Using the energy method: abs((mef.intWm*2)/(mef.ICoil_1^2)) = 226.09 uH
Why does the latter return an indutance which is exactly 50% of the built-in inductance calculation?
--
:)
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Posted:
8 years ago
Hello Yngve,
Be carefull, when you compute mef.ICoil_1^2, try instead sqrt(real(mef.ICoil)^2+imag(mef.ICoil)^2)/sqrt(2).
The result should be different.
Best regards
Julien
Be carefull, when you compute mef.ICoil_1^2, try instead sqrt(real(mef.ICoil)^2+imag(mef.ICoil)^2)/sqrt(2).
The result should be different.
Best regards
Julien
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Posted:
8 years ago
Thank you for your insight, Julien.
Why is there a difference, and more importantly: which one is the actual coil inductance?
edit: I got the same result when i used this formula: (mef.intWm*2) / (abs(mef.ICoil_1/sqrt(2))^2)
--
:)
Why is there a difference, and more importantly: which one is the actual coil inductance?
edit: I got the same result when i used this formula: (mef.intWm*2) / (abs(mef.ICoil_1/sqrt(2))^2)
--
:)