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The dumbest thing I've ever seen in amp construction....
The dumbest thing I've ever seen in amp construction....
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Old 16th May 2019, 04:25 AM   #11
cmjohnson is offline cmjohnson  United States
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Originally Posted by Enzo View Post
And yet all those thousands of PV amps soldier on for decades and decades, blissfully unaware they cannot possibly function the way they are built. Those incredibly loud and toneful amps are like bumblebees. We all remember learning that from an engineering point of view, bumblebees cannot fly.
Having shorted windings does not prevent the transformers from functioning as transformers. Whatever caused you to think that they would stop working with shorted laminations? I never said any such thing.

But their efficiency is compromised. They're going to draw more current and run hotter than an equivalent transformer with properly insulated laminations. Nothing more.
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Old 16th May 2019, 04:27 AM   #12
abraxalito is offline abraxalito  United Kingdom
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And yet all those thousands of PV amps soldier on for decades and decades, blissfully unaware they cannot possibly function the way they are built.
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Old 16th May 2019, 04:28 AM   #13
cmjohnson is offline cmjohnson  United States
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Again, nobody said that having shorted laminations will keep the transformer from functioning as a transformer. It just becomes LESS EFFICIENT, wasting energy, getting hotter than it should. And heating affects component life.
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Old 16th May 2019, 04:30 AM   #14
abraxalito is offline abraxalito  United Kingdom
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Eddy currents, hysteresis losses...they're related phenomena. It would be more accurate to describe the main issue as one of eddy currents and I'll admit that I should have said that to start with.
I don't see that they're related other than they both occur in a typical core material. But we get eddy currents in copper (hence Litz wire) and no hysteresis effects that I'm aware of. And in ferrite cores we get hysteresis but no eddy currents. But good for you in realizing your error, there is hope
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Old 16th May 2019, 04:39 AM   #15
GKTAUDIO is offline GKTAUDIO  United States
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https://www.electronics-tutorials.ws...struction.html

Discusses laminate insulation varnish or oxide, insulated fixing bolts.

Last edited by GKTAUDIO; 16th May 2019 at 04:45 AM.
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Old 16th May 2019, 04:40 AM   #16
cmjohnson is offline cmjohnson  United States
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So if laminations don't have to be insulated from each other, why are there even laminations? It's extra work to make them. If that extra work serves no purpose, then why is it that laminated core transformers make up the bulk of transformers? Yes, there are ferrite core transformers, but that material has LOW electrical conductivity coupled with high magnetic permeability so that makes sense for the very same reason that it makes sense for steel laminations to be insulated.

It's a defining characteristic of good transformer design that the magnetic core material will exhibit high (or controlled) magnetic permeability and low electrical conductivity.

You just don't find any transformer company anywhere that makes lump iron/steel core transformers or that welds across laminations. Ask any transformer design engineer about welding across the laminations. See what he thinks.
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Old 16th May 2019, 04:47 AM   #17
abraxalito is offline abraxalito  United Kingdom
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Originally Posted by cmjohnson View Post
So if laminations don't have to be insulated from each other, why are there even laminations?
Your difficulty might just stem from black/white thinking. Why divide things into conductor/insulator? Why not consider that in reality there's a continuum (or spectrum) of conductivity?

Here's a quote from Bertrand Russell which you may (or may not) find relevant :https://www.azquotes.com/vangogh-ima...d-25-49-01.jpg
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Last edited by abraxalito; 16th May 2019 at 04:59 AM.
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Old 16th May 2019, 04:54 AM   #18
mctavish is offline mctavish  Austria
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Haha, When I looked at the first picture I thought the dumb thing was how close the two power tubes are to each other..... Look how big the chassis is.

Waaaaay to close....
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Old 16th May 2019, 06:29 AM   #19
trobbins is offline trobbins  Australia
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It is worthwhile appreciating that core losses relate to the flux density in the section of core that is of interest. Note that the weld line is at a small point on the extremity of each lamination's area. Negligible flux flows through the weld point on the lamination - if anything it is leakage flux from air returning to the core in that location.
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Old 16th May 2019, 06:41 AM   #20
voltwide is offline voltwide  Ireland
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Exactly - there are more xformers on planet earth with welding - and they all are laminated and isolated. Obviously there is no way to argument with strong believers.
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