Calculate the inductance of a solenóide wound on an iron core

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Discussion Overview

The discussion centers around calculating the inductance of a solenoid wound on an iron core, specifically addressing the complexities introduced by the core's relative permeability and the presence of air in the magnetic path. Participants explore theoretical aspects and practical implications related to the inductance calculation.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants express uncertainty about how to calculate the inductance of a solenoid with a given cross-sectional area and length, along with an iron core of high relative permeability.
  • One participant suggests that the effective permeability of the core will be significantly lower than the stated value of 9,000 due to the presence of air in the magnetic path.
  • Another participant notes that for an air core, the formula includes the permeability of free space (uo), while for an iron core, it should also account for the effective permeability of the magnetic path.
  • There is a request for an example calculation that incorporates the effective permeability and the wire gauge, indicating a lack of familiarity with the relevant equations.
  • Participants discuss the formula for magnetic field (B) and question whether it is missing a division by length (L), reflecting uncertainty about the correct application of the formula.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the calculation method or the implications of the effective permeability, indicating that multiple competing views remain regarding the inductance calculation for the solenoid.

Contextual Notes

There are unresolved assumptions regarding the effective permeability and the specific parameters needed for the calculations, as well as potential dependencies on the definitions of terms used in the discussion.

Teslas
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Hello friends of the forum! I'm here with a doubt! I have a solenoid of cross-sectional area 5cm and length 9cm with iron core of relative permeability (ur) 9,000, I wonder how to calculate this silenoid!
 
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Teslas said:
Hello friends of the forum! I'm here with a doubt! I have a solenoid of cross-sectional area 5cm and length 9cm with iron core of relative permeability (ur) 9,000, I wonder how to calculate this silenoid!
I think the difficulty is that the effective permeability of the core will be much less than 9,000 because the magnetic path is partly air. This problem comes up in connection with ferrite rod antennas, and there is an article here: http://g3rbj.co.uk/wp-content/uploads/2014/06/Web-The-Inductance-of-Ferrite-Rod-Antennas-issue-3.pdf
 
IMG

tech99 said:
I think the difficulty is that the effective permeability of the core will be much less than 9,000 because the magnetic path is partly air. This problem comes up in connection with ferrite rod antennas, and there is an article here: http://g3rbj.co.uk/wp-content/uploads/2014/06/Web-The-Inductance-of-Ferrite-Rod-Antennas-issue-3.pdf
My question is
Code: 
  [ATTACH=full]238238[/ATTACH]
 

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Teslas said:
IMG


My question is
2gvv4gh.gif
 

Attachments

  • 2gvv4gh.gif
    2gvv4gh.gif
    47.4 KB · Views: 782
Teslas said:
IMG


My question is
2gvv4gh.gif
 

Attachments

  • 2gvv4gh.gif
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    47.4 KB · Views: 779
In the case of the air core, we see the formula with uo in it. But for the second case, iron core, we must also multiply by the effective mu of the magnetic path.
 
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[QUOTE = "tech99, post: 6127760, member: 477979"] No caso do núcleo de ar, vemos a fórmula com uo nela. Mas para o segundo caso, núcleo de ferro, devemos também multiplicar pelo mu efetivo do caminho magnético. [/ QUOTE]
Amigo, obrigada por me responder! Estou tentando fazer um eletroímã! E eu não conheço a bitola do fio, não sei a equação, alguém poderia colocar um exemplo com essa fórmula que eu coloquei? Yess permeability magnetc of iron core yesss!
 
This question is magnéticFild ( B)
 
Teslas said:
This question
tech99 said:
In the case of the air core, we see the formula with uo in it. But for the second case, iron core, we must also multiply by the effective mu of the magnetic path.

You are correct, we must multiply by the magnetic permeability of the vac (uo) together with the permeability of the magnetic nucleus (ur) in this image that I put, I am in doubt in this formula, B = k.uo.nl, this formula is missing divide by length (L) am I right?
 

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