Formulas and calculators > Coil winding
how to detect eddy currents and measure their negative impact
brandnewb:
Please excuse me if I am totally blundering. But I would really like to see if my premise has any merit or not. Also I am going out on a limb here so I might be mistaken on the physics behind it all. That subject never was my strong point ;(
My premise is that traditional laminated sheets for coils are sub optimal. The sheets still conduct electricity. Because there is a tiny gap between the sheets the effect of eddy currents induced by magnets rotating over them is reduced but not eliminated.
I would like to introduce a totally new way of going about things in this day and age but before I do so I will need to be able to demonstrate that the concept is indeed an improvement over traditional.
Something I am certainly not ready yet to without a doubt through out into the world at this stage. {2} But I want to believe!. Famous quotes The X files{2}
Please see the only stator of a 3 phase single stator alternator that I like to end up with. The rotors (magnets are on both sides but just not displayed here)
The idea is to have the coil disk engulfed with aluminum powder filled resin on the outskirts and the coils them self with iron powder filled resin.
I am imagining the incredible heat dissipation ability increase over just plain resin should I have understood things correctly and there are no unforeseen road blocks ahead.
Also for each magnet group (1 pair in both sides making 4 magnets in total) there are 3 coils. 1 for each phase. So basically there is a continues loop with minimal interruptions.
I have been trying to demonstrate in a convincing manner that the iron powder I am using does not (or at the very least much less than traditional laminated sheets) produce eddy currents because the powder is not electro conductive.
Early test results suggest I am on the right track but I am also known for making huge blunders so I need to take this a bit more scientific before I start making bold claims.
Please see the latest test setup I used. Earlier setups that made me think this is indeed worth exploring are horrendous and unwieldy.
The distance between the magnets is roughly 28mm and the field strength is around 120 mili tesla where I can get my probe at.
The central disk is non compacted (just gravity filled) iron powder. To more closely resemble the state it would be in when cast in resin.
Something like this.
In this current configuration there central bearing will contribute to the central disk rotating when I use a hand held drill to spin the magnets over the disk.
But it could also be that there is also the eddy current induced drag we all fear.
I did try rotating the magnets rather fast back and forth back and forth for like 1.5 minutes at full rotation drill speed and there is simply no heat build up that I can detect.
How do I make sure I am on the right track here?
{1] @SparWeb, please allow me to quote a line from your signature.
"No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it."
If coping quotes is a no no then please delete this addit{1}
mab:
I kind of feel you've answered your own question: if you want to measure eddy current losses then you measure the drag induced in the rotating rotors or the heat generated in the medium under test.
Not sure what you mean by laminated sheets - unless you mean laminated iron cores which are not usually used in AF Generators. But if you are referring to laminated iron cores then to compare with your powder cores, you would need to do the same eddy current tests on a laminated iron core too.
brandnewb:
please find here an example of what I meant with laminated sheets in coils
https://www.fieldlines.com/index.php/topic,149398.msg1062917.html#msg1062917
I just no longer believe this is still a good way of going about things.
{1}the sentence above is far to harsh. I meant to say I no longer believe this is still the most ideal way of making alternators.{1}
I guess I meant to ask how can I convince the rest of us?
{2} I'll revisit this when I have the iron powder disk completely isolated so only eddy currents can make it rotate. No longer also bearing friction{2}
brandnewb:
Does anyone know where I can buy premade laminated sheets in Europe that are used in coils? I can't seem to find any.
I will need this to compare results.
JW:
Hey nice CAD drawings... I run Solidworks 2019 and its awesome. As far go,s getting material you have to imposes/compromise
JW
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