300W Resistive load?
in [Design]
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From: Joerg on 17 Jul 2010 10:37 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'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 :-) 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 ... -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Jan Panteltje on 17 Jul 2010 11:25 On a sunny day (Sat, 17 Jul 2010 10:21:07 -0400) it happened Hammy <spam(a)spam.com> wrote in <8re346lphhfcb8ndc5guqkq0n44kb0a6hj(a)4ax.com>: >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.I'll look around for some >small cheap bulb mounts. Please note that when cold a lightbulb is 1/10 the resistance. So you supply may not start up at all. Better take apart some electric heater.
From: Hammy on 17 Jul 2010 11:39 On Sat, 17 Jul 2010 15:25:20 GMT, Jan Panteltje <pNaonStpealmtje(a)yahoo.com> wrote: >On a sunny day (Sat, 17 Jul 2010 10:21:07 -0400) it happened Hammy ><spam(a)spam.com> wrote in <8re346lphhfcb8ndc5guqkq0n44kb0a6hj(a)4ax.com>: > >>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.I'll look around for some >>small cheap bulb mounts. > >Please note that when cold a lightbulb is 1/10 the resistance. >So you supply may not start up at all. >Better take apart some electric heater. I have NTC inrush limiters for that. It should also take some ms for the controller to start-up during this time the bulbs would be supplied from a rectified line, should heat them up enough. The controller is supposed to hiccup anyways in the event of a short. But you are right if I do run into start-up problems I'll look into that.
From: Hammy on 17 Jul 2010 11:45 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. > >> ... 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 :-) >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.;-)
From: Jamie on 17 Jul 2010 12:21
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. toster oven ? |