Reduction of eddy currents' magnetic field during induction

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Discussion Overview

The discussion revolves around the reduction of eddy currents' magnetic field during induction, particularly in the context of using laminated magnetic cores and permanent magnets in applications like generators. Participants explore various aspects of magnetic materials, their properties, and practical considerations in design.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant inquires about the placement of laminated magnetic cores and their availability from manufacturers, expressing a preference for natural permanent magnets.
  • Another participant suggests that the context may involve a transformer, asking for clarification on the use of natural permanent magnets.
  • A different participant states that all commercially available permanent magnets are artificially magnetized and discusses the importance of retentivity in different applications, noting that low retentivity is desired for cores in systems with alternating magnetic flux.
  • One participant describes their setup involving a linear generator and poses questions about eddy current losses, methods to minimize them, and cooling techniques.
  • Another participant mentions that in the context of a homopolar generator, a conventional method to reduce eddy currents is to arrange the magnetic field to avoid inducing recirculating currents.

Areas of Agreement / Disagreement

Participants express differing views on the properties of permanent magnets and the relevance of eddy currents in various applications. There is no consensus on the best approach to minimize eddy currents or the optimal type of magnetic material to use.

Contextual Notes

Participants have not fully resolved the implications of using natural versus artificially magnetized materials, nor have they reached a conclusion on the effectiveness of different cooling methods or the specifics of eddy current losses in their proposed setups.

Who May Find This Useful

Individuals interested in magnetic materials, generator design, and the effects of eddy currents in electrical engineering applications may find this discussion relevant.

adeborts
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Since the field in the title is opposing the original magnetic flux that causes the induction, how can it be reduced?
I understand that a laminated magnetic core can be used.
1) Where is this magnetic laminated core placed?
2) Can it be obtained from specialized manufacturers?
3) My choice for the permanent magnet is the natural kind. Would this be the best choice, given that artificially magnetized materials lose their strength in time?

Sorry for the awkward, all-over-the-place manner in which I post the questions.
I am ignorant and eager.

I appreciate, beforehand, the knowledge and patience of all respondents.
 
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adeborts said:
) Where is this magnetic laminated core placed?
Sounds like you are talking about a transformer. The windings are wound on the core.
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adeborts said:
My choice for the permanent magnet is the natural kind.
Could you elaborate?
 
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All commercially available permanent magnets are artificially magnetized. Reducing eddy current is unimportant unless the core permits alternating magnetic flux (such as electric motor armature, antenna core, or transformer). You want the retentivity of the ferromagnetic core to be as low as possible in those cases.

In a permanent magnet, it's the opposite. The greater the retentivity, the better.
 
Many thanks to both!

Here is what's going on:

I have access to a primary source of energy which I would use to maintain the motion of a translator in a linear generator.
In my mind, the translator would be a natural permanent magnet.
- What are the losses due to the eddy currents during the process?
How do I minimize those?
- What about the heating?
What is the best cooling method?
- Any other caveats?

Thanks.
 
If you're talking about a homopolar generator, the conventional way to reduce eddy current is to arrange the magnetic field so that it doesn't induce current that recirculates.
 
David Lewis said:
If you're talking about a homopolar generator, the conventional way to reduce eddy current is to arrange thye magnetic field so that it doesn't induce current that recirculates.

Thank you.
 

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