Does Every Iron Core Have the Same Relative Permeability?

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Discussion Overview

The discussion centers on the relative permeability of iron cores, particularly in the context of electromagnets and transformers. Participants explore how the permeability varies with current and the implications for magnetic field strength.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant notes that the magnetic field B can be enhanced using a high permeability core, questioning the average relative permeability (μr) of iron and whether all iron has the same μr.
  • Another participant suggests that high permeability ferromagnetic cores enable electromagnets to achieve magnetic fields of a Tesla or higher.
  • It is mentioned that for most iron, the permeability (μ) changes significantly with current (I), indicating a dependence on the application of the core.
  • A request for elaboration on how μr varies with current is made, along with a query about whether μr values are constant at zero or a specific current, and a claim that μr can exceed 1000 for ferromagnets.
  • Participants differentiate between soft and hard magnetic materials, discussing their respective properties related to coercivity and hysteresis loops.

Areas of Agreement / Disagreement

Participants express differing views on the variability of relative permeability in iron cores, particularly in relation to current and application. There is no consensus on whether all iron cores share the same relative permeability.

Contextual Notes

Limitations include the lack of specific values or examples regarding the relative permeability of different types of iron and the conditions under which these values may change.

Who May Find This Useful

This discussion may be of interest to those studying electromagnetism, materials science, or engineering applications involving magnetic materials.

Dash-IQ
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B = μ0nI
Usually, the value of B is quite small...
I'd like to boost the magnetic field B to a much larger and stronger field, and the most efficient way I find to do that is using a high permeability core B = ku0nI.
What is the average μr of an iron core? They range from what value?
Do all iron have the same relative permeability?
 
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+ With the use of a high permeability ferromagnetic cores, it makes it more practical for electromagnets to have a magnetic field a Tesla and possibly higher?
 
For most iron, mu changes drastically with I.
It also depends on what you want the core to do. For an electromagnet or transformer you want B to go back to zero elastically when I goes to zero. For more permanent magnetism, you want a fat hysteresis loop.
 
Meir Achuz said:
For most iron, mu changes drastically with I.

Can you elaborate please on that(i.e example with values)?
Are ur of ferromagnets based on I? or are they a constant value when I = 0 or I = x Amps?
Is it true that their ur are over a 1000?

The rest I'm quite familiar with, as you are describing soft core(e.g iron low coercivity), and hard core's that are best when creating permanent magnets with(e.g neodymium low coercivity wider hysteresis area).
 

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