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Welding on an output transformer
Welding on an output transformer
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Old 16th May 2019, 05:10 AM   #11
cmjohnson is offline cmjohnson  United States
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I regularly deal with a number of EEs and every one of them laughed and shook their heads when I pointed out a few cases similar to this one, all various Peavey amps, over the years. Not one of them thinks that it's anything resembling good engineering practice to weld a transformer across its laminations. Such a questionable practice flies in the face of all the electronics education I've acquired since 1975.
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Old 16th May 2019, 05:25 AM   #12
abraxalito is offline abraxalito  United Kingdom
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Quote:
Originally Posted by cmjohnson View Post
Such a questionable practice flies in the face of all the electronics education I've acquired since 1975.
Its been a bit narrow, hasn't it? Your electronics education I mean. Since 1975 it has only concerned eddy currents in transformers and how laminations avoid them?
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Old 16th May 2019, 06:01 AM   #13
trobbins is offline trobbins  Australia
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It is most likely the initial shock and knee jerk reaction to seeing that style of construction for the first time. It does require some magnetics thought to appreciate what can change and how influential it is. Sort of like when people worry themselves silly about the outer surface of their power transformer having signs of rust.

It's closest equivalence is probably a mounting bolt that passes through a hole in the core and doesn't use insulated washers to avoid inducing a circulating current.
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Old 16th May 2019, 12:08 PM   #14
Kay Pirinha is offline Kay Pirinha  Germany
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See my answer here: The dumbest thing I've ever seen in amp construction....
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Old 16th May 2019, 12:31 PM   #15
Osvaldo de Banfield is offline Osvaldo de Banfield  Argentina
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I agree with cmjohnson. Welding the lamination becomes it loosier and too difficult to repair/disassemble.
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Old 16th May 2019, 01:19 PM   #16
cmjohnson is offline cmjohnson  United States
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Questioning my electronics education is not a good idea. While I'm not a designing engineer, I do technician work in all phases of electronics from basic linear to multi-frequency, multi-phase switching power supplies to audio, video, RF, and digital troubleshooting and repair. I did seven years as the chief technician in a two way radio shop and have worked in avionics in addition to multiple various other positions. My education is very broad based. If it consumes electricity I can understand it and fix it when it's broken, at the component level. I'm not one of those "technicians" who fixes things by swapping out a circuit board.

Among other things I did the system design and oversaw the deployment of multiple radio systems in multiple countries. Digital trunked radio system design is a specialty art and I do it.

Abraxalito, you, on the other hand, have difficulty comprehending even the requirement and reasoning for transformer laminations. Basic first month of electronics education stuff. You should not be talking.

Last edited by cmjohnson; 16th May 2019 at 01:21 PM.
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Old 16th May 2019, 01:54 PM   #17
Osvaldo de Banfield is offline Osvaldo de Banfield  Argentina
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I work in repairing industrial equipment, I saw lots of this kind of inductors an transformers made in such a way, and sincerely I'm in doubt how the quality of the iron is altered after the welding process. Also, several inductors for choke input at the three phases systems use welded inductor WITHOUT GAP that is a not good design, IMHO.
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Old 16th May 2019, 10:09 PM   #18
Mark Tillotson is offline Mark Tillotson
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Welding on the outside of the core doesnt do anything. Welding on the inside and on the outside would create a conducting loop, but just doing the outside doesn't create any current loops. Draw it out if unsure...
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Old 17th May 2019, 12:03 AM   #19
trobbins is offline trobbins  Australia
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Engineering is often about managing compromises, and appreciating all aspects, not just technical.

The assumption is that a company made a poor engineering decision - but the reasoning presented is imho lacking in any engineering perspective. I see no balanced assessment of the likely considerations that went in to the decision to use welding for that application, or any evidence of performance comparisons of an example transformer that has been made the 'Peavey' way versus what has been considered the 'right' way.

Imho, if you lambast Peavey with multiple posts, then back it up with evidence and assessment, or accept the critique that heading a thread with 'the dumbest thing' comes back at you.

I think the topic is very valid to discuss, and tease out what degradation of performance it may incur, and why particular applications have come around to using it. I order in and manufacture with choke cores that are supplied with welded laminations - so for my particular application, I have been down a similar path, and do recall the knee-jerk concern when first seeing such a core.
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