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Old 21st May 2022, 4:27 am   #11
joebog1's Avatar
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,382
Default Re: SE transformer question

.5mm or 20 thou is pretty chunky iron !!. "Most " transformer iron is .35 mm, or 14 thou. Special iron
( mainly, for dare I mention it, chokes and HIGH quality SE service is 7 thou )
can handle somewhat more flux density, and has a much better stack factor, providing it is stamped from a sharp die. As mentioned, John Sankey ( Newcastle Australia ) were specialists in lamination production, and made some of the very best ever available. If you can find some old or burned 2nd hand iron, and are still on your self education, I would recommend another try if you are not overly successful first time around. Sectioning is another thing to look at, as is winding with bifilar or tri filar winding tecniques. This reduces gaps or voids and distsributes the current over a wider winding area.

I have, on several occasions wound SE stuff in verticle sections, rather than horizontal sections.
They measured better, but sounded the same. They also run cooler.
Of greatest importance is wire tension when winding. Exactly the same wire tension has always created a better transfomer, as has precise insulation between layers. I still prefer paper insulation, rather than mylar tape for the best examples.
Known as onion paper, it used be available down to 1.5 thou thickness. Was supplied by "Mica and Insulating Supplies Sydney " now long deceased of course. Mostly useless information now, but just me musing on SE transformers, and chokes. I posted it hoping you will derive some useful information.

My best regards

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