Jan Panteltje wrote: =====================> In the UPS case you do not charge into an _empty_ capacitor, if the UPS functions right > then it is just the discharge difference from the last mains period (depends on wallwart load), > the peak current will be limited also by the resistance of the series diodes, > and by the Zi from the UPS etc.. >**Yep.> Square wave charges for a longer time,** Nonsense. No charging pulses AT ALL. It's fucking DC you fool. ..... Phil
Inverters vs wallwarts
Started by ●June 24, 2022
Reply by ●June 26, 20222022-06-26
Reply by ●June 26, 20222022-06-26
On Sun, 26 Jun 2022 05:00:35 -0700 (PDT), Phil Allison <pallison49@gmail.com> wrote:> Jan Panteltje wrote: > >===================== > >> In the UPS case you do not charge into an _empty_ capacitor, if the UPS functions right >> then it is just the discharge difference from the last mains period (depends on wallwart load), >> the peak current will be limited also by the resistance of the series diodes, >> and by the Zi from the UPS etc.. >> > **Yep. > >> Square wave charges for a longer time, > >** Nonsense. > >No charging pulses AT ALL. >It's fucking DC you fool. > > > >..... PhilThey're talking about wallwarts loading the output of a UPS inverter that generates a 120VAC output with either a square or sine waveform. Capacitive rectified input filters of the wallwarts' primary(SMPS), or capacitive rectified output filters of the wallwart's (linear) secondaries will produce a different 120VAC current crest factor, depending on whether they are fed by a square or sine wave. If a square wave has it's simplest form (+-120V ~180degree, then crest factor is low, but the capacitive rectified output voltage will be only 70% of that produced by a 120V sine source. If the square vave is tailored to produce a more similar output (peak to RMS ratio), with higher voltage at a reduced duty cycle, then crest factor of rectified current will increase, and can easily exceed that of the sinusoidal standard input. Input current will look more like an RC charge/discharge, than a haversine charge/RC discharge. RL
Reply by ●June 26, 20222022-06-26
On a sunny day (Sun, 26 Jun 2022 08:43:40 -0400) it happened legg <legg@nospam.magma.ca> wrote in <9jjgbhhjkqbqjr4krsm1g9dco3oc495k2d@4ax.com>:>On Sun, 26 Jun 2022 05:00:35 -0700 (PDT), Phil Allison ><pallison49@gmail.com> wrote: > >> Jan Panteltje wrote: >> >>===================== >> >>> In the UPS case you do not charge into an _empty_ capacitor, if the UPS functions right >>> then it is just the discharge difference from the last mains period (depends on wallwart load), >>> the peak current will be limited also by the resistance of the series diodes, >>> and by the Zi from the UPS etc.. >>> >> **Yep. >> >>> Square wave charges for a longer time, >> >>** Nonsense. >> >>No charging pulses AT ALL. >>It's fucking DC you fool. >> >> >> >>..... Phil > >They're talking about wallwarts loading the output of >a UPS inverter that generates a 120VAC output with either >a square or sine waveform. > >Capacitive rectified input filters of the wallwarts' >primary(SMPS), or capacitive rectified output filters >of the wallwart's (linear) secondaries will produce a >different 120VAC current crest factor, depending on >whether they are fed by a square or sine wave. > >If a square wave has it's simplest form (+-120V ~180degree, >then crest factor is low, but the capacitive rectified >output voltage will be only 70% of that produced by a 120V >sine source. > >If the square vave is tailored to produce a more similar >output (peak to RMS ratio), with higher voltage at a >reduced duty cycle, then crest factor of rectified current >will increase, and can easily exceed that of the sinusoidal >standard input. Input current will look more like an RC >charge/discharge, than a haversine charge/RC discharge. > >RLHere the waveform of my cheap UPS loaded with a normal 25 W lightbulb: http://www.panteltje.com/pub/APC_UPS_ES700_waveform_25W_edison_bulb_load_IMG_0270.JPG measured a while back when it was new, 230V AC 50Hz Europe, cannot read the Vpp from the picture but 230 * sqrt(2) = 325, *2 = 650 Vpp this looks like 5 to 6 divisions maybe around 500 to 600 Vpp (not sure). Waveform is interesting :-)
Reply by ●June 26, 20222022-06-26
On Sun, 26 Jun 2022 13:29:08 GMT, Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:>On a sunny day (Sun, 26 Jun 2022 08:43:40 -0400) it happened legg ><legg@nospam.magma.ca> wrote in <9jjgbhhjkqbqjr4krsm1g9dco3oc495k2d@4ax.com>: > >>On Sun, 26 Jun 2022 05:00:35 -0700 (PDT), Phil Allison >><pallison49@gmail.com> wrote: >> >>> Jan Panteltje wrote: >>> >>>===================== >>> >>>> In the UPS case you do not charge into an _empty_ capacitor, if the UPS functions right >>>> then it is just the discharge difference from the last mains period (depends on wallwart load), >>>> the peak current will be limited also by the resistance of the series diodes, >>>> and by the Zi from the UPS etc.. >>>> >>> **Yep. >>> >>>> Square wave charges for a longer time, >>> >>>** Nonsense. >>> >>>No charging pulses AT ALL. >>>It's fucking DC you fool. >>> >>> >>> >>>..... Phil >> >>They're talking about wallwarts loading the output of >>a UPS inverter that generates a 120VAC output with either >>a square or sine waveform. >> >>Capacitive rectified input filters of the wallwarts' >>primary(SMPS), or capacitive rectified output filters >>of the wallwart's (linear) secondaries will produce a >>different 120VAC current crest factor, depending on >>whether they are fed by a square or sine wave. >> >>If a square wave has it's simplest form (+-120V ~180degree, >>then crest factor is low, but the capacitive rectified >>output voltage will be only 70% of that produced by a 120V >>sine source. >> >>If the square vave is tailored to produce a more similar >>output (peak to RMS ratio), with higher voltage at a >>reduced duty cycle, then crest factor of rectified current >>will increase, and can easily exceed that of the sinusoidal >>standard input. Input current will look more like an RC >>charge/discharge, than a haversine charge/RC discharge. >> >>RL > >Here the waveform of my cheap UPS loaded with a normal 25 W lightbulb: > http://www.panteltje.com/pub/APC_UPS_ES700_waveform_25W_edison_bulb_load_IMG_0270.JPG > >measured a while back when it was new, >230V AC 50Hz Europe, cannot read the Vpp from the picture >but 230 * sqrt(2) = 325, *2 = 650 Vpp >this looks like 5 to 6 divisions maybe around 500 to 600 Vpp (not sure). >Waveform is interesting :-)That's the modified square wave. It will produce quite peaky current waveforms in a capacitive rectified filter. But, as you've said, if it works, it works. The OP was trying to predict performance, based on insufficient information. RL
Reply by ●June 26, 20222022-06-26
On Sun, 26 Jun 2022 10:27:49 -0400, legg <legg@nospam.magma.ca> wrote:>On Sun, 26 Jun 2022 13:29:08 GMT, Jan Panteltje ><pNaonStpealmtje@yahoo.com> wrote: > >>On a sunny day (Sun, 26 Jun 2022 08:43:40 -0400) it happened legg >><legg@nospam.magma.ca> wrote in <9jjgbhhjkqbqjr4krsm1g9dco3oc495k2d@4ax.com>: >> >>>On Sun, 26 Jun 2022 05:00:35 -0700 (PDT), Phil Allison >>><pallison49@gmail.com> wrote: >>> >>>> Jan Panteltje wrote: >>>> >>>>===================== >>>> >>>>> In the UPS case you do not charge into an _empty_ capacitor, if the UPS functions right >>>>> then it is just the discharge difference from the last mains period (depends on wallwart load), >>>>> the peak current will be limited also by the resistance of the series diodes, >>>>> and by the Zi from the UPS etc.. >>>>> >>>> **Yep. >>>> >>>>> Square wave charges for a longer time, >>>> >>>>** Nonsense. >>>> >>>>No charging pulses AT ALL. >>>>It's fucking DC you fool. >>>> >>>> >>>> >>>>..... Phil >>> >>>They're talking about wallwarts loading the output of >>>a UPS inverter that generates a 120VAC output with either >>>a square or sine waveform. >>> >>>Capacitive rectified input filters of the wallwarts' >>>primary(SMPS), or capacitive rectified output filters >>>of the wallwart's (linear) secondaries will produce a >>>different 120VAC current crest factor, depending on >>>whether they are fed by a square or sine wave. >>> >>>If a square wave has it's simplest form (+-120V ~180degree, >>>then crest factor is low, but the capacitive rectified >>>output voltage will be only 70% of that produced by a 120V >>>sine source. >>> >>>If the square vave is tailored to produce a more similar >>>output (peak to RMS ratio), with higher voltage at a >>>reduced duty cycle, then crest factor of rectified current >>>will increase, and can easily exceed that of the sinusoidal >>>standard input. Input current will look more like an RC >>>charge/discharge, than a haversine charge/RC discharge. >>> >>>RL >> >>Here the waveform of my cheap UPS loaded with a normal 25 W lightbulb: >> http://www.panteltje.com/pub/APC_UPS_ES700_waveform_25W_edison_bulb_load_IMG_0270.JPG >> >>measured a while back when it was new, >>230V AC 50Hz Europe, cannot read the Vpp from the picture >>but 230 * sqrt(2) = 325, *2 = 650 Vpp >>this looks like 5 to 6 divisions maybe around 500 to 600 Vpp (not sure). >>Waveform is interesting :-) > >That's the modified square wave. It will produce quite peaky >current waveforms in a capacitive rectified filter. > >But, as you've said, if it works, it works. The OP was trying to >predict performance, based on insufficient information. > >RLI can imagine a fast rise heating up the first cap in a non-PFC wart. Their usual failure mode is a bad cap. Might stress the usual series resistor too. A temperature comparison wouldn't be difficult. (I'm designing power supplies lately, and cap esr heating is part of the puzzle.)
Reply by ●June 26, 20222022-06-26
On a sunny day (Sun, 26 Jun 2022 10:27:49 -0400) it happened legg <legg@nospam.magma.ca> wrote in <asqgbh545t97hl10p0mlm2j66li2pe42tq@4ax.com>:>On Sun, 26 Jun 2022 13:29:08 GMT, Jan Panteltje ><pNaonStpealmtje@yahoo.com> wrote: >>Here the waveform of my cheap UPS loaded with a normal 25 W lightbulb: >> http://www.panteltje.com/pub/APC_UPS_ES700_waveform_25W_edison_bulb_load_IMG_0270.JPG >> >>measured a while back when it was new, >>230V AC 50Hz Europe, cannot read the Vpp from the picture >>but 230 * sqrt(2) = 325, *2 = 650 Vpp >>this looks like 5 to 6 divisions maybe around 500 to 600 Vpp (not sure). >>Waveform is interesting :-) > >That's the modified square wave. It will produce quite peaky >current waveforms in a capacitive rectified filter. > >But, as you've said, if it works, it works. The OP was trying to >predict performance, based on insufficient information.Yes, and most of the wallwarts I have have a big input voltage range like 110 to 230 V AC. That gives the UPC some time to come in in case of 230V :-)
Reply by ●June 26, 20222022-06-26
legg wrote: =============== Phil Allison> > > > >> Square wave charges for a longer time, > > > >** Nonsense. > > > >No charging pulses AT ALL. > >It's fucking DC you fool. > >> > If a square wave has it's simplest form (+-120V ~180degree, > then crest factor is low, but the capacitive rectified > output voltage will be only 70% of that produced by a 120V > sine source. >** The man said " square wave " - over and over.> If the square vave is tailored to produce a more similar > output (peak to RMS ratio), with higher voltage at a > reduced duty cycle, >** Not a *square wave* any more. ..... Phil
Reply by ●June 27, 20222022-06-27
On Sat, 25 Jun 2022 07:32:27 -0400, legg <legg@nospam.magma.ca> wrote:>On Sat, 25 Jun 2022 02:10:59 -0000 (UTC), bob prohaska ><bp@www.zefox.net> wrote: > >>I'm setting up a UPS for my computer/comms equipment using an >>inverter/charger and battery from Amazon. The equipment draw >>is only about 40 watts measured with a Kill-A-Watt, but all >>the associated wallwarts use capacitive-input switching power >>supplies. That means they only draw current at line peaks. >> >>My seat-of-the-pants guess is that the duty cycle is around 10%, >>meaning that the average 40 watts is really 400 watts 10% of the time. >>That's well within the continuous power rating of the inverter, which >>is 800 watts, so it's likely the setup will work as it is. >> >>The question is: Can the peak load be made closer to the average >>load by putting an inductor in the AC line feeding the wallwarts? >> >>If anybody's been through this exercise I'd be grateful for guidance. >> >>Thanks for reading, >> >>bob prohaska >> >> > >I did some passive correction for off-the-shelf 60Hz linears in >the 80s. Best effects achieved using a saturable choke and >quasi-resonant capacitor, over a limited range of power levels >for any specific installation. > >The parts are generally impractical for a hobbyist to get >ahold of, though restacking laminations from unvarnished scrap >is possible. Requires good VP Impregnation to silence the >final iteration. > >The actual current phase angle shifted from leading to lagging >over the useful range. Output voltage into the 60Hz capacitive >load was flat-topped, affecting the low-line voltage performance. >The choke/cap combination supported the output difference >during line current reversal. > >It's no good guessing what the current waveshape is; you've >got to measure it / scope it. Line current transformers are >pretty cheap these days, often included in <$10 wattmeters >from off-shore sources. A scope is useful, but more expensive. > >A lot of modern wall-warts are actually PFC compliant, through >the use of dedicated low power integrated controllers. These >employ valley-fill or critical-conduction (FM) off-line switchers >economically, at power levels as low as 5W. > >Don't guess. Measure. Read specs of devices involved. > >Don't go overboard. Your UPS output may be more tolerant of peak >loads than you assume, and your loads may be less peaky, simply >due to industry commodity trends and available parts. > >RLSome work on different rectifier and filter/pre-filter circuitry was published by Richard Redl and Laszlo Balogh ~1995. Some notes I made in the 80s, on the simplest LC configuration are also included in this zip file. In the latter, the effect of series choke saturation at above- nominal loads is illustrated. http://ve3ute.ca/query/passive_power_factor_diag.zip When standards docs start talking about total harmonic distortion and specs include power factors >95%, you can pretty much rule out passive approaches. They can be simple, reliable, quiet and effective in reducing generator and interconnection losses. . . . which is the OP's actual concern. RL
Reply by ●June 27, 20222022-06-27
On Friday, June 24, 2022 at 10:11:06 PM UTC-4, bob prohaska wrote:> I'm setting up a UPS for my computer/comms equipment using an > inverter/charger and battery from Amazon. The equipment draw > is only about 40 watts measured with a Kill-A-Watt, but all > the associated wallwarts use capacitive-input switching power > supplies. That means they only draw current at line peaks. > > My seat-of-the-pants guess is that the duty cycle is around 10%, > meaning that the average 40 watts is really 400 watts 10% of the time. > That's well within the continuous power rating of the inverter, which > is 800 watts, so it's likely the setup will work as it is. > > The question is: Can the peak load be made closer to the average > load by putting an inductor in the AC line feeding the wallwarts? > > If anybody's been through this exercise I'd be grateful for guidance. > > Thanks for reading,Look at the plug-in output voltage inverter-fed versus line-fed. If no difference, then no issue. Look at the inverter RMS output with and without a bunch of plug-ins. If no difference then no issue.> > bob prohaska
Reply by ●June 27, 20222022-06-27
On Saturday, June 25, 2022 at 1:24:40 AM UTC-4, John Doe wrote:> Jan Panteltje <pNaonSt...@yahoo.com> wrote: > > bob prohaska wrote: > > > >>I'm setting up a UPS for my computer/comms equipment using an > >>inverter/charger and battery from Amazon. The equipment draw is only > >>about 40 watts measured with a Kill-A-Watt, but all the associated > >>wallwarts use capacitive-input switching power supplies. That means > >>they only draw current at line peaks. > >> > >>My seat-of-the-pants guess is that the duty cycle is around 10%, meaning > >>that the average 40 watts is really 400 watts 10% of the time. That's > >>well within the continuous power rating of the inverter, which is 800 > >>watts, so it's likely the setup will work as it is. > >> > >>The question is: Can the peak load be made closer to the average load by > >>putting an inductor in the AC line feeding the wallwarts? > >> > >>If anybody's been through this exercise I'd be grateful for guidance. > > Interesting question, my cheap UPS seems to put out a square wave I > > wondered if the flat tops are actually not better for the wall warts as > > the charging part is longer than with a sine wave top... Been working > > now fine for a year or so with this thing, comes in almost every day > > these days with mains company fiddling,.. flashing light bulbs sometimes > > here too. To backup for longer times I have a pure sine wave 2 kW > > converter and a 250 Ah lifepo4 battery.. So I can keep watching sat TV > > or even cook food. More than 10 wallwarts on that UPS now, some > > Raspberry Pi, some USB hubs, some cameras., also security recorder, > > monitors... .. audio amp... 4 TB harddisks... I would personally not > > bother with a a series inductor... > For a personal computer only... I use a Tripp-Lite LC1200. No battery at > all. I don't recall the last time we had a power failure that lasted more > than an moment. But there has been flickering. The line conditioner works > great for momentary outages, no messing with a battery. > > Of course that doesn't suit everybody.They just lifted the same technology used in inverter generators. If it coasts through what you call a momentary outage then it wasn't an outage. The price is pretty good but then again 1200 Watt is not really that much. Are you mining bitcoins or something? What in the world kind of computer setup requires 1200W these days...
