Quick, what's wrong with this picture?
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The BRILLIANT mechanical engineers at Peavey clearly never had a moment's conversation with the ELECTRICAL engineers.
BOTH transformers are WELDED to sub plates.
The welds are ACROSS ALL THE LAMINATIONS.
Thus, all the laminations are electrically SHORTED, rather than being insulated, to reduce eddy currents (Edited, I originally stated hysteresis losses, which is not correct.) . That's WHY transformers are made with laminated cores instead of solid metal cores, which would be easier to make.
Peavey did this to BOTH transformers in this amp, and also did the exact same thing to other amplifiers they made in the 70s and 80s. (But not to every model.)
What does this do to the transformer?
It becomes inefficient. It wastes energy. It gets hotter than it should for a given power loading. It reduces the usable bandwidth of the transformer.
That is the single dumbest manufacturing choice I've ever seen made in a commercially available production electronic product.
An externally hosted image should be here but it was not working when we last tested it.
Scroll down....
.
.
.
SEE IT???
The BRILLIANT mechanical engineers at Peavey clearly never had a moment's conversation with the ELECTRICAL engineers.
BOTH transformers are WELDED to sub plates.
The welds are ACROSS ALL THE LAMINATIONS.
Thus, all the laminations are electrically SHORTED, rather than being insulated, to reduce eddy currents (Edited, I originally stated hysteresis losses, which is not correct.) . That's WHY transformers are made with laminated cores instead of solid metal cores, which would be easier to make.
Peavey did this to BOTH transformers in this amp, and also did the exact same thing to other amplifiers they made in the 70s and 80s. (But not to every model.)
What does this do to the transformer?
It becomes inefficient. It wastes energy. It gets hotter than it should for a given power loading. It reduces the usable bandwidth of the transformer.
That is the single dumbest manufacturing choice I've ever seen made in a commercially available production electronic product.
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I was under the impression laminations were for reducing eddy current losses. Hysteresis losses wouldn't be altered would they as they're just material dependent? In a laminated transformer the laminations aren't actually insulated from each other, they're in contact with each other - the resistance being much higher between laminations than within a lamination.
Eddy current loss takes place when a coil is wrapped around a core and alternating ac supply is applied to it. ... Due to insulated sheets the amount of current which flows get reduced and hence the eddy current losses.
Hysteresis Loss: The amount of energy absorbed by the magnetic material which is not returned back.
Both are affected by the lamination construction.
Oh, believe me, those laminations are most certainly insulated from each other! Every lamination is individually varnished and/or chemically treated to apply an insulative oxide layer before the laminations are assembled and bonded together.
I've taken apart many transformers over the years. I've never found one of any size that didn't have varnished and oxide coated laminations.
Hysteresis Loss: The amount of energy absorbed by the magnetic material which is not returned back.
Both are affected by the lamination construction.
Oh, believe me, those laminations are most certainly insulated from each other! Every lamination is individually varnished and/or chemically treated to apply an insulative oxide layer before the laminations are assembled and bonded together.
I've taken apart many transformers over the years. I've never found one of any size that didn't have varnished and oxide coated laminations.
I can assure you beyond any possible doubt, every transformer you ever encountered has laminations that are electrically insulated from each other.
Feel free to test this. Rip apart any random old transformer and start metering from lamination to lamination.
https://www.electronics-tutorials.ws/transformer/transformer-construction.html
If the laminations are not insulated from each other, there is absolutely no point whatsoever in even using laminations.
Feel free to test this. Rip apart any random old transformer and start metering from lamination to lamination.
https://www.electronics-tutorials.ws/transformer/transformer-construction.html
If the laminations are not insulated from each other, there is absolutely no point whatsoever in even using laminations.
So then equally well, there would be no point in using Litz wire where the strands weren't perfectly insulated from one another. But wait, turns out there is : http://engineering.dartmouth.edu/inductor/papers/stranded.pdf
Litz wire has nothing to do with the reason for why transformer laminations exist and why they're electrically insulated from each other.
I'm quite certain that all my electronics instructors and textbooks that I've learned electronics from starting in 1975 have not all been lying to me about how and why transformers are constructed and their operating principles. To discover the whole world has been lying to me for 44 years would be rather disappointing.
It is not until this topic was created and my conversation with you started that I have "learned" that transformer laminations aren't insulated from each other.
One of us is wrong in his beliefs about transformer laminations and how they work and why they're made that way. Hopefully this will serve to correct misinformation through additional reading and study.
I'm quite certain that all my electronics instructors and textbooks that I've learned electronics from starting in 1975 have not all been lying to me about how and why transformers are constructed and their operating principles. To discover the whole world has been lying to me for 44 years would be rather disappointing.
It is not until this topic was created and my conversation with you started that I have "learned" that transformer laminations aren't insulated from each other.
One of us is wrong in his beliefs about transformer laminations and how they work and why they're made that way. Hopefully this will serve to correct misinformation through additional reading and study.
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.
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.
But I'm absolutely certain beyond doubt that every textbook you care to bring up when you Google search for "transformer laminations insulated" will tell you clearly that yes, transformer laminations are electrically insulated from each other. You'd have a very hard time explaining why all those textbooks are wrong.
But I'm absolutely certain beyond doubt that every textbook you care to bring up when you Google search for "transformer laminations insulated" will tell you clearly that yes, transformer laminations are electrically insulated from each other. You'd have a very hard time explaining why all those textbooks are wrong.
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.
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
https://www.electronics-tutorials.ws/transformer/transformer-construction.html
Discusses laminate insulation varnish or oxide, insulated fixing bolts.
Discusses laminate insulation varnish or oxide, insulated fixing bolts.
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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.
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.
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-image-quotes/25/49/Quotation-Bertrand-Russell-The-whole-problem-with-the-world-is-that-fools-and-25-49-01.jpg
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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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