115/230V voltage switch key for transformer?
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From: Rich Grise on 25 Nov 2009 17:42 On Wed, 25 Nov 2009 12:34:38 -0800, Joerg wrote: > >> BTW, how do you pronounce "Joerg?" :-) >> > It's o-umlaut, pronounced just like Archie Bunker and many New Yorkers say > "poifect" or "point". "Joig?" Or maybe "Yoig?" If "Euler" is pronounced, "Oiler," then howcome "Euclid" isn't pronounced "Oiclid?" ;-) Thanks, Rich
From: Rich Grise on 25 Nov 2009 17:43 On Wed, 25 Nov 2009 14:42:01 -0800, Rich Grise wrote: > On Wed, 25 Nov 2009 12:34:38 -0800, Joerg wrote: >> >>> BTW, how do you pronounce "Joerg?" :-) >>> >> It's o-umlaut, pronounced just like Archie Bunker and many New Yorkers >> say "poifect" or "point". > > "Joig?" Or maybe "Yoig?" > > If "Euler" is pronounced, "Oiler," then howcome "Euclid" isn't pronounced > "Oiclid?" ;-) > PS. I was thinking maybe "Yerg". ;-) Oops - I think the vodka might be kicking in... Thanks, Rich
From: Herman on 25 Nov 2009 17:56 "Joerg" <invalid(a)invalid.invalid> wrote in message news:7n5in7F3jmflvU1(a)mid.individual.net... > Rich Grise wrote: >> On Wed, 25 Nov 2009 11:31:18 -0800, Joerg wrote: >>> krw wrote: >>>> On Wed, 25 Nov 2009 10:25:01 -0800, Joerg <invalid(a)invalid.invalid> >>>>> osr(a)uakron.edu wrote: >>>>>> Yeah, the ON circuit is crude, and the SCRs in series are a failure >>>>>> point. But its a start. >>>>>> And from a safety point of view, its got to be more of a hazard then >>>>>> a >>>>>> properly made jumper. >>>>>> Kinda my point. >>>>>> >>>>>> I take it this is on a linear for noise or cost reasons? >>>>>> >>>>> Two reasons. The cost of transformers is remarkably low, around five >>>>> bucks for 10-15VA. Can't beat that with a switcher, even considering >>>>> your own PWM stuff behind it because that only adds a buck or two. >>>>> >>>>> Then, temperature. Beats me but all the places I've called won't >>>>> endorse more than 50C or 60C for their switcher modules and that's >>>>> just >>>>> not going to fly. For some reason my own designs never had such limits >>>>> but I can't justify the NRE for all the agency testing on this one if >>>>> we rolled our own mains-connected switcher. >>>>> >>>>> The only 250V-rated selectors I see are panel mount and insanely >>>>> expensive, such as this one: >>>>> >>>>> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=0033.1118-ND >>>> How about a wall wart? You should be able to find something like that >>>> for $10-$15. >>> The only way to get one in would be to snip the end off a two-prong >>> Christmas extension code, solder it in and strap the whole kludge down >>> with cable ties. Any fire marshall would blow a gasket ;-) >>> >>> Plus I think wall warts don't like to bake in there. >> >> What exactly is it you're trying to produce? You've given several >> different conflicting scenarios here. Is the user supposed to be >> responsible for selecting the voltage? Does it get set at the factory? >> What code are you trying to satisfy? >> >> Please, Joerg, tell us the "big picture" here. >> > > Ok, big picture follows: > > Unit in fields, outdoors, think farm. The sun is pelting it brutally all > day long and the electric stuff sits inside an enclosure, no vents big > enough to write home about. No choice, it has to be that way and it works > fine in a 120V version. > > Client wants users to be able to ideally just plug it into 120 or 240, and > not worry about a thing. That ain't going to fly because SMPS modules seem > to not be that great. Maybe cheap electrolytics, I don't know, but mfgs > don't want to endorse >60C and it sure does get hotter than that in there. > Just by the sun. > > So, the next best avenue would be a configurable 120/240 transformer > because then we can have our own (better) switcher behind that. > Unfortunately the cheap voltage selectors have become pariahs. > > Configuring at the factory would be ok but it has to be simple, like > flicking a hidden switch or reversing an insert. But it (meaning also that > switching element) must be code-compliant, in this case UL as well as VDE > (CE) plus later some others, maybe Japan. Up to now it was only UL. > > Cost is critical. Adding a buck in total is ok, adding five bucks is not. > > >> BTW, how do you pronounce "Joerg?" :-) >> > > It's o-umlaut, pronounced just like Archie Bunker and many New Yorkers say > "poifect" or "point". > > -- > Regards, Joerg > > http://www.analogconsultants.com/ > > "gmail" domain blocked because of excessive spam. > Use another domain or send PM. See if this will work for you. http://s936.photobucket.com/albums/ad204/rike2/
From: Jamie on 25 Nov 2009 18:42 Joerg wrote: > Rich Grise wrote: > >> On Tue, 24 Nov 2009 17:48:09 -0800, Joerg wrote: >> >>> Hello Folks, >>> >>> Never needed this before but now I do: What are those things called that >>> you unplug and insert 180 degrees rotated to switch the primaries of a >>> transformer between 115V operation (parallel) and 230V operation >>> (series)? >>> Circuit board mount. >>> >>> Or better yet, does anyone know a source? Must be super cheap, as in >>> <<50c >>> altogether in qties, as usual :-) >>> >>> Under categories such as "voltage selector" I only found fuse holders >>> with >>> this feature in there, really expensive plus way too large. I want to >>> avoid a slide switch because someone could accidentally hit it and ... >>> *PHUT* >> >> >> Jumper? >> > > Very much against code, usually. Unless it's a wire jumper but my client > wants to avoid having to open the units every time an order comes in for > the "wrong" voltage. > The universal supplies are such a nice idea.. ~100 .. 240 volts input. etc... Some start as low as 24 volts AC/DC
From: krw on 25 Nov 2009 18:40
On Wed, 25 Nov 2009 11:31:18 -0800, Joerg <invalid(a)invalid.invalid> wrote: >krw wrote: >> On Wed, 25 Nov 2009 10:25:01 -0800, Joerg <invalid(a)invalid.invalid> >> wrote: >> >>> osr(a)uakron.edu wrote: >>>> Yeah, the ON circuit is crude, and the SCRs in series are a failure >>>> point. But its a start. >>>> And from a safety point of view, its got to be more of a hazard then a >>>> properly made jumper. >>>> Kinda my point. >>>> >>>> I take it this is on a linear for noise or cost reasons? >>>> >>> Two reasons. The cost of transformers is remarkably low, around five >>> bucks for 10-15VA. Can't beat that with a switcher, even considering >>> your own PWM stuff behind it because that only adds a buck or two. >>> >>> Then, temperature. Beats me but all the places I've called won't endorse >>> more than 50C or 60C for their switcher modules and that's just not >>> going to fly. For some reason my own designs never had such limits but I >>> can't justify the NRE for all the agency testing on this one if we >>> rolled our own mains-connected switcher. >>> >>> The only 250V-rated selectors I see are panel mount and insanely >>> expensive, such as this one: >>> >>> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=0033.1118-ND >> >> >> How about a wall wart? You should be able to find something like that >> for $10-$15. > > >The only way to get one in would be to snip the end off a two-prong >Christmas extension code, solder it in and strap the whole kludge down >with cable ties. Any fire marshall would blow a gasket ;-) > >Plus I think wall warts don't like to bake in there. I was thinking about putting the wall wart elsewhere and run your widget off DC. How about using your 240V transformer (or dual primary in series) with a secondary voltage high enough at 120V to run your switcher or perhaps a buck-boost switcher. Let it run at 1/2V at 120V. |