300W Resistive load?
in [Design]
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From: JosephKK on 20 Jul 2010 07:41 On Sat, 17 Jul 2010 09:56:36 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Martin Riddle wrote: >> "Joerg" <invalid(a)invalid.invalid> wrote in message >> news:8ae3skFnekU1(a)mid.individual.net... >>> Hammy wrote: >>>> On Sat, 17 Jul 2010 07:37:28 -0700, Joerg <invalid(a)invalid.invalid> >>>> wrote: >>>> >>>>> Hammy wrote: >>>>>> On Sat, 17 Jul 2010 07:00:35 -0700, Joerg <invalid(a)invalid.invalid> >>>>>> wrote: >>>>>> >>>>>>> Hammy wrote: >>>>>>>> What is something cheap and simple that can be used to dissapate >>>>>>>> 300W >>>>>>>> on a 200Vdc bus. I'm trying to think of something I could maybe >>>>>>>> pick >>>>>>>> up at a local homedepot or similiar. >>>>>>>> >>>>>>>> I need a 300W load to test out my PFC. >>>>>>> Light bulbs? Two in series and then as many of those in parallel >>>>>>> as needed. >>>>>> Sounds good one 60W bulb is about 200 ohms. ... >>>>> At 200V each bulb gets only 100V so the resistance will be a little >>>>> lower. You could measure that if it must be precise. >>>> I don't need high precision if I can test at even 80% rated load and >>>> maybe do some pulse test and off course use a CT to check the input >>>> current I'll be happy. >>> >>> Well, just wanted to mention that because when at undervoltage the >>> bulbs >>> will present a higher load. Also, when you start any kind of converter >>> from zero they will almost look like a short initially. Same if you >>> connect a cold bulb (cold filament) to a running converter. It's not >>> like a power resistor. >>> >>> >>>>>> ... I'll look around for some small cheap bulb mounts. >>>>> You can also solder to them. If careful they can later still be used >>>>> for >>>>> their intended purpose. But make sure you place them onto a heat >>>>> resistant surface during the test :-) >>>> Your taking all the fun out of this :-) >>>> >>> The fun might come back when connecting the cold bulbs not two by two, >>> but all at once. Tchk ... *POOF*. >>> >>> >>>>> Good news is you may not even have to drive all the way to Home >>>>> Depot. >>>>> Supermarkets also have a variety of them. Of course, then your wife >>>>> might hand you a lengthy "while you are there anyhow" list and you >>>>> don't >>>>> get to look at all the new power tools, barbecues and stuff. Man's >>>>> toy >>>>> store ... >>>> We call that a honey do list here.;-) >>>> >>> Nah, a honey-do list isn't grocery shooping, it's when the missus >>> wants >>> you to get that tree stump out over yonder, and it's 105F :-) >>> >>> -- >> >> >> Better pick up extra incandescent bulbs, comes 2014, you wont be able to >> get them here in the US. >> > >Probably not quite. First, there'll be another election before then and >... well, we'll see. > >Then the ban extends down to 40W AFAIK. I am sure some clever business >will start selling 39W light bulbs. The basic idea seems to come from >Poland: > >http://mojapolskadomowa.blox.pl/resource/zarwka99w.jpg > >A gray market might also develop. In Germany where 100W bulbs have been >banned long since they are still happily selling them: > >http://www.lampenwelt.de/Leuchtmittel/Gluehlampen/E27-Gluehlampen/E27-15W-100W-Gluehlampe-matt.html > >As for frosted ones which were particularly frowned upon by regulators >the page states "Bei Lampenwelt.de erhalten Sie matte Gl�hlampen noch >aus gr��eren Restbest�nden. Lieferung sofort ab Lager solange der Vorrat >reicht!" which means " ... frosted light bulbs from large overstock. >Prompt delivery as long as stock lasts!". For some reason it must have >lasted more than a year by now :-) > >Ban, compliance, two different things it seems. Oh yea. They forced a stop of manufacturing, but the existing inventory should last well past 2020, allowed to be sold while the supply lasts. Moreover, it does not much affect specialty lamp versions.
From: JosephKK on 20 Jul 2010 07:46 On Sat, 17 Jul 2010 12:02:47 -0700 (PDT), mpm <mpmillard(a)aol.com> wrote: >On Jul 17, 11:56�am, Joerg <inva...(a)invalid.invalid> wrote: >> Martin Riddle wrote: >> > "Joerg" <inva...(a)invalid.invalid> wrote in message >> >news:8ae3skFnekU1(a)mid.individual.net... >> >> Hammy wrote: >> >>> On Sat, 17 Jul 2010 07:37:28 -0700, Joerg <inva...(a)invalid.invalid> >> >>> wrote: >> >> >>>> Hammy wrote: >> >>>>> On Sat, 17 Jul 2010 07:00:35 -0700, Joerg <inva...(a)invalid.invalid> >> >>>>> wrote: >> >> >>>>>> Hammy wrote: >> >>>>>>> What is something cheap and simple that can be used to dissapate >> >>>>>>> 300W >> >>>>>>> on a 200Vdc bus. I'm trying to think of something I could maybe >> >>>>>>> pick >> >>>>>>> up at a local homedepot or similiar. >> >> >>>>>>> I need a 300W load to test out my PFC. >> >>>>>> Light bulbs? Two in series and then as many of those in parallel >> >>>>>> as needed. >> >>>>> Sounds good one 60W bulb is about 200 ohms. ... >> >>>> At 200V each bulb gets only 100V so the resistance will be a little >> >>>> lower. You could measure that if it must be precise. >> >>> I don't need high precision if I can test at even 80% rated load and >> >>> maybe do some pulse test and off course use a CT to check the input >> >>> current I'll be happy. >> >> >> Well, just wanted to mention that because when at undervoltage the >> >> bulbs >> >> will present a higher load. Also, when you start any kind of converter >> >> from zero they will almost look like a short initially. Same if you >> >> connect a cold bulb (cold filament) to a running converter. It's not >> >> like a power resistor. >> >> >>>>> �... I'll look around for some small cheap bulb mounts. >> >>>> You can also solder to them. If careful they can later still be used >> >>>> for >> >>>> their intended purpose. But make sure you place them onto a heat >> >>>> resistant surface during the test :-) >> >>> Your taking all the fun out of this :-) >> >> >> The fun might come back when connecting the cold bulbs not two by two, >> >> but all at once. Tchk ... *POOF*. >> >> >>>> Good news is you may not even have to drive all the way to Home >> >>>> Depot. >> >>>> Supermarkets also have a variety of them. Of course, then your wife >> >>>> might hand you a lengthy "while you are there anyhow" list and you >> >>>> don't >> >>>> get to look at all the new power tools, barbecues and stuff. Man's >> >>>> toy >> >>>> store ... >> >>> We call that a honey do list here.;-) >> >> >> Nah, a honey-do list isn't grocery shooping, it's when the missus >> >> wants >> >> you to get that tree stump out over yonder, and it's 105F :-) >> >> >> -- >> >> > Better pick up extra incandescent bulbs, comes 2014, you wont be able to >> > get them here in the US. >> >> Probably not quite. First, there'll be another election before then and >> ... well, we'll see. >> >> Then the ban extends down to 40W AFAIK. I am sure some clever business >> will start selling 39W light bulbs. The basic idea seems to come from >> Poland: >> >> http://mojapolskadomowa.blox.pl/resource/zarwka99w.jpg >> >> A gray market might also develop. In Germany where 100W bulbs have been >> banned long since they are still happily selling them: >> >> http://www.lampenwelt.de/Leuchtmittel/Gluehlampen/E27-Gluehlampen/E27... >> >> As for frosted ones which were particularly frowned upon by regulators >> the page states "Bei Lampenwelt.de erhalten Sie matte Gl�hlampen noch >> aus gr��eren Restbest�nden. Lieferung sofort ab Lager solange der Vorrat >> reicht!" which means " ... frosted light bulbs from large overstock. >> Prompt delivery as long as stock lasts!". For some reason it must have >> lasted more than a year by now :-) >> >> Ban, compliance, two different things it seems. >> >> -- >> Regards, Joerg >> >> http://www.analogconsultants.com/ >> >> "gmail" domain blocked because of excessive spam. >> Use another domain or send PM.- Hide quoted text - >> >> - Show quoted text - > >Yeah.... and then we'll have to deal with all the advertising hype for >those "innovative" companies that come up with a 39.9 W bulb and claim >some benefit derived therefrom. > >I wonder if this is how that extra 9/10th of a cent per gallon we pay >at the gas pump came into being..??? :) Marketing. Just $9.99. Thus under $10. Humans tend to brain slip on this, sometimes to the point of thinking $8.88 is more than $9.99. Marketing. &,(
From: JosephKK on 20 Jul 2010 08:02 On Sat, 17 Jul 2010 07:26:36 -0700 (PDT), whit3rd <whit3rd(a)gmail.com> wrote: >On Jul 17, 6:36�am, Hammy <s...(a)spam.com> wrote: >> What is something cheap and simple that can be used to dissapate 300W >> on a 200Vdc bus. > >Maybe two or three electric irons in parallel. > >If this will be anything other than a temporary lashup, >you'll want a fuse rated to interrupt 200VDC. A typical electric clothes iron (flatiron for those that remember) is about 450 W rated, with a bang-bang temperature controller.
From: JosephKK on 20 Jul 2010 08:04 On Sat, 17 Jul 2010 12:43:29 -0400, John Ferrell <jferrell13(a)triad.rr.com> wrote: >Small electric heater with switch able power level. > >I don't know about now, but in the distant past hardware stores sold >heating elements that screwed into porcelain light sockets. The >intended use was for chicken incubators. > >On Sat, 17 Jul 2010 09:36:24 -0400, Hammy <spam(a)spam.com> wrote: > >>What is something cheap and simple that can be used to dissapate 300W >>on a 200Vdc bus. I'm trying to think of something I could maybe pick >>up at a local homedepot or similiar. >> >>I need a 300W load to test out my PFC. >John Ferrell W8CCW I have actually seen those sold for room heaters (with dish reflector) at powers a high as 1000 W.
From: JosephKK on 20 Jul 2010 08:18
On Sun, 18 Jul 2010 08:28:44 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: >On Sun, 18 Jul 2010 08:05:57 -0400, Hammy <spam(a)spam.com> wrote: > >>On Sun, 18 Jul 2010 06:25:40 -0500, "Tim Williams" >><tmoranwms(a)charter.net> wrote: >> >>>"Nico Coesel" <nico(a)puntnl.niks> wrote in message news:4c42bd4b.224380781(a)news.planet.nl... >>>>>What is something cheap and simple that can be used to dissapate 300W >>>>>on a 200Vdc bus. I'm trying to think of something I could maybe pick >>> ^^^^^^ >>>>>up at a local homedepot or similiar. >>>>> >>>>>I need a 300W load to test out my PFC. >>>> >>>> I've constructed an adjustable dummy load by using 4 TO3 transistors >>>> from an old switching power supply. A heatsink and a couple of fans >>>> take care of the heat. The whole thing isn't much larger than a shoe >>>> box. >>> >>>Doesn't work in this case though, you'll be in the second breakdown region. Unless it was slightly less old and used TO-3 MOSFETs, which Idunno, might be worth something on eBay. :^) >>> >>>Hammy might have a few FETs left over from the boost though, they would handle the voltage just fine, as long as there's enough for the power. >>> >>>Tim >>FETS I have a lot of. I also have some nice(2) brick heatsinks I >>scavenged from some old microwave oven and car stero ampslifier. >> >>Thta was my original thought but I was thinking it would take to many >>to dissapate the power 275W. >> >>The biggest I have in quantity is the FQA24N50 TO-3PN >> >>http://www.fairchildsemi.com/ds/FQ/FQA24N50.pdf >> >>I have about 30 of those. >> >> Actually those are in a pretty beefy package maybe 5 on a brick with >>a fan might work. >> >> >>I also have about 40 of these FQP27N25 TO-220 >> >>http://www.fairchildsemi.com/ds/FQ/FQP27N25.pdf >> >>Both of those Newark had on for dirt cheap and I was buying ten of >>each everytime I did an order. Figured they might come in handy at >>some time.;-) >> >>I have 1 or 2 IRF350 in to-3 no suitable heatsink for that power >>level. > >Finned heat sinks, arranged as a square tunnel, fins inward, file, >mill, whatever so they fit together nicely, and the "square" is >muffin-fan size... which fits on one end. > > ...Jim Thompson Yup. Also works fine with pairs and any air blocker to make a tunnel. There will be a thermal gradient along the tunnel, with FETs this works in your favor though. |