Transformer insulateing tape?
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From: Perenis on 20 Jun 2010 15:13 On Sun, 20 Jun 2010 11:53:29 -0700 (PDT), Wimpie <wimabctel(a)tetech.nl> wrote: >> � And why is it you wish to split the primary winding and place half >> UNDER the secondary, and half OVER the secondary? > >Reducing leakage induction. Sure. One should... where it is NEEDED. No need... no do. In this app, I'd be willing to bet that the operational efficiency gain would be no more than a single percentage point or two.
From: Perenis on 20 Jun 2010 15:19 On Sun, 20 Jun 2010 11:53:29 -0700 (PDT), Wimpie <wimabctel(a)tetech.nl> wrote: >He mentions it is line-powered, The UNIT is, not the transformer. I would feel reasonably sure that the hammster does not need to worry about his AC flashing through to the operator. Andif it doe, he'll trash it and build another. > so you have to account for over >voltages and whether single or double/reinforced insulation is >requried, even when the output voltage is 5V. If Hammy doesn't have EN >60950, or 60065 at hand, he may search for ECMA-287. He has stated SEVERAL times that this is NOT a product! > It can be >downloaded free and gives good guidance on creepage, clearance, >insulation requirements, etc. He knows about that already. SO DO I. The only difference is that *I* DID read the thread, and *I* DO know what his considerations for this are. It is for his personal lab. First, he wants quick and dirty to prove the design. Then, he MIGHT fine tune it, characterize it, or 'dial-it-in'. If it works right on the first jab, he might just be done with it and get back to his other bench work.
From: Hammy on 20 Jun 2010 15:25 On Sun, 20 Jun 2010 12:19:45 -0700, Perenis <Perenis(a)hereforlongtime.org> wrote: >On Sun, 20 Jun 2010 11:53:29 -0700 (PDT), Wimpie <wimabctel(a)tetech.nl> >wrote: > >>He mentions it is line-powered, > > The UNIT is, not the transformer. > > I would feel reasonably sure that the hammster does not need to worry >about his AC flashing through to the operator. Andif it doe, he'll trash >it and build another. > >> so you have to account for over >>voltages and whether single or double/reinforced insulation is >>requried, even when the output voltage is 5V. If Hammy doesn't have EN >>60950, or 60065 at hand, he may search for ECMA-287. > > He has stated SEVERAL times that this is NOT a product! > >> It can be >>downloaded free and gives good guidance on creepage, clearance, >>insulation requirements, etc. > > He knows about that already. SO DO I. The only difference is that *I* >DID read the thread, and *I* DO know what his considerations for this >are. It is for his personal lab. > > First, he wants quick and dirty to prove the design. Then, he MIGHT >fine tune it, characterize it, or 'dial-it-in'. If it works right on the >first jab, he might just be done with it and get back to his other bench >work. Exactly. Thanks for reading the requirments.;-)
From: Perenis on 20 Jun 2010 15:29 On Sun, 20 Jun 2010 19:05:42 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Sun, 20 Jun 2010 11:59:21 -0700) it happened Perenis ><Perenis(a)hereforlongtime.org> wrote in ><85ps169h4p5qbdcnk77le8j5vg1qk48dpe(a)4ax.com>: > >>On Sun, 20 Jun 2010 14:06:54 -0400, Hammy <spam(a)spam.com> wrote: >> >>> >>>>That said, I have wound a TV hor output transformer with normal A4 paper as isolation. >>>>As long as temperature stays low, and it does not get wet, it works. >> >> Only up to about 1000V isolation (that's generous). Without >>impregnation, that paper looks like it is not even there to the excited >>electron. Even through several layers of it. D'oh! > >Sure, but how much voltage you have between layers if you wind in a normal way >is something you can calculate. >1000 V is a lot, much more then was dealing with. >Say if you have 1 turn per volt, for arguments sake, >and 100 turns per layer, 3 layers, then there is no problem. >IIRC I used about 1 turn per volt 440 turns for the H scan coil drive winding >Long time ago, BW TV, my school days, tubes, worked nicely. How many layers did that end up as? All it takes to breach the mag wire at the vpt is about 300 turns, so it also would have to have been flat wound. Can't go that high with a scatter wind, and regardless of your claim, an overvoltage event would punch through that like a needle through skin if the lead-out wire (or turns) are anywhere near the lead-in.
From: Jan Panteltje on 20 Jun 2010 15:33
On a sunny day (Sun, 20 Jun 2010 15:25:31 -0400) it happened Hammy <spam(a)spam.com> wrote in <9kqs16p9evdl9lh8ikt3l6uqkg5ecmrnrj(a)4ax.com>: >> First, he wants quick and dirty to prove the design. Then, he MIGHT >>fine tune it, characterize it, or 'dial-it-in'. If it works right on the >>first jab, he might just be done with it and get back to his other bench >>work. > > >Exactly. > >Thanks for reading the requirments.;-) Any mains isolation could be solved by putting windings on separate legs and using 2 U cores.... Earth the core. Safer not possible. |