Is there a book or an article on the places where the voltage potential across the core is minimal allowing the laminations to be connected?
What are you looking to achieve? Some transformers have a weld across the laminates to cut down on noise but it is not done often. Old microwave transformers were an example.
You mostly do not want laminations to conduct at more than one point. You will have losses. Usually laminations are insulated to avoid this.
You mostly do not want laminations to conduct at more than one point. You will have losses. Usually laminations are insulated to avoid this.
@edgarsls
Seems like you might be trying to solve some problem. If so, whatever it may be, most likely connecting transformer laminations together is not the best solution. We could talk about why that is, or maybe we could just help if there is something about sound that needs fixing? Happy to try 🙂
Seems like you might be trying to solve some problem. If so, whatever it may be, most likely connecting transformer laminations together is not the best solution. We could talk about why that is, or maybe we could just help if there is something about sound that needs fixing? Happy to try 🙂
Some transformers have a weld across the laminates to cut down on noise but it is not done often. Old microwave transformers were an example.
Disagree on the "not done often" ....These days, with rising labour costs one has to take into account easier ways of mass producing, i.e non critical microwave trannies, general main trannies where many have a weld across laminations for one thing only. It saves time some person having to alternatively stack E&I laminations when machines are quicker. The other, that separately stacking all the E´s and welding the "I"s leaving a gap spews out stray magnetic flux. That does NOT go down well in the audio world. Although in a sense all E&I output trannies have an inherent lamination end gap, substituting this with a welded E&I lump would play with the leakage flux proximity in relation to the gap and the sectionalized windings. Conceptual magnetics is a subject beyond this forum. The best example can be illustrated by the school experiment of scattering iron filings on paper with a magnet wth an with a gap similat to an E&I.
Welding the stack on a power transformer with Bmax at the near limit is NOT the done thing. ......The pic below has hand stacked laminations for an obvious reason; reducing lossy eddy currents.
Bench Baron
Painting with a wide brush, flux tries to travel along the least resistance path (duh!) so in principle it tries to travel along the lamination E or I centerlines, much less on the edges.
That's why laminations are insulated on their main surfaces by paint/varnish/paper/oxydation but no special care is taken on punched edges, where metal is exposed and makes lamination to lamination contact with no problem.
Bolt holes are punched on corners or opposite the center E leg again because of less flux there.
That's why laminations are insulated on their main surfaces by paint/varnish/paper/oxydation but no special care is taken on punched edges, where metal is exposed and makes lamination to lamination contact with no problem.
Bolt holes are punched on corners or opposite the center E leg again because of less flux there.
For those budding with
The link https://www.ti.com/seclit/ml/slup132/slup132.pdf Magnetics design handbook.
The article deals mainly with switchmode power frequencies, however the correlation holds true for any transformer particulary for audio and line frequencies, esp the section of core losses and eddy currents.
Keep one´s hair on and drift through it !
For those of us who have worked in large work-halls, from my previous pic..
Notice the very careful handling of the silicon iron sheet.
Bench Baron
No one shouldn´t give up, if that is what you are implying. To grapple with a subject that appears a black art (which many sadly appear to believe); ... from my Uni in the mid 1960´s I followed the work of Lloyd Dixon from Unitrode Corp, and I believe is the only clear account to bring some ease in a complicated subject. Yes, it´s op´end physics, but those who are building tube amps and power supplies from scratch, unless it´s a kit to be assembled, will probably have some idea of magnetics and physics. There is no escape.....
The link https://www.ti.com/seclit/ml/slup132/slup132.pdf Magnetics design handbook.
The article deals mainly with switchmode power frequencies, however the correlation holds true for any transformer particulary for audio and line frequencies, esp the section of core losses and eddy currents.
Keep one´s hair on and drift through it !
For those of us who have worked in large work-halls, from my previous pic..
Bench Baron