Re (2): UPS with earth leakage device.
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From: david on 7 Jan 2010 22:57 On Thu, 07 Jan 2010 18:41:17 +0000, ArameFarpado rearranged some electrons to say: > Em Quinta 07 Janeiro 2010 08:27, no.top.post(a)gmail.com escreveu: > >> In article <4b44e3c5$0$275$14726298(a)news.sunsite.dk>, ArameFarpado >> <a-farpado.spam(a)netcabo.pt> wrote: >> >>> Em Quarta 06 Janeiro 2010 17:23, no.top.post(a)gmail.com escreveu: >>> > But I can't understand since the UPS is designed to switch on AFTER >>> > the mains failure. >>> >>> wrong. >> >> OK, I don't want to influence original contributions, by giving my full >> present analysis. But the failure process takes a finite time. And I >> insist that the UPS can only acts AFTER the beginning of the mains >> 'failure process'. >> >> Can you contribute more than "wrong" ? > > You are confusing a UPS with a emergency electric generator; those are > the ones that start working after the power goes off. A UPS needs to > keep the power up without letting it go down even for a split second. > > The only switch a ups does when the power goes off is that it stops > charging the batteries. The output of a UPS is allways given by the same > circuits regardless if the power is on or off > > with power on: > > main power -> AC-DC converter -> DC-AC converter -> output > -> charge batteries. > > with power off: > > batteries -> DC-AC converter -> output > > > > this is the only way that an ups can keep the output on without any > breaks. > > > > so resuming: if the ups's output is given the wrong voltage, frequency, > sinosoidal wave, etc... you have two choices: 1- repair the ups > 2- replace the ups. > > regards This is only true with a double-conversion type UPS, which most cheap PC- type UPS's are not. Most cheap UPSs have a transfer switch in them, so the power is actually interrupted for a few milliseconds when the mains fail.
From: ArameFarpado on 8 Jan 2010 03:05 Em Sexta 08 Janeiro 2010 01:40, Joe Pfeiffer escreveu: > ArameFarpado <a-farpado.spam(a)netcabo.pt> writes: > >> Em Quinta 07 Janeiro 2010 08:27, no.top.post(a)gmail.com escreveu: >> >>> No, AFAIK the earth-leakage -detector works by measuring >>> the unbalance between the line and neutral current flow. >>> Since the unbalance must be returning via the earth. >>> So REMOVING THE EARTH to the UPS & computer circuit >>> 'eliminates the problem'. But that's a bodge. >>> One needs to fully understand the problem cause >>> sequence. >>> . >>> == TIA. >> >> if you have electrical questions, it's better to put them in >> sci.electronics.basics >> >> >> i can tell you that if you desconnect the earth, ther will be no more a >> neutral in the output, you will have two live lines with a voltage >> between them, and that could cause other issues. > > You can tell us anything you want, but if you tell us that you're > wrong. Standard single-phase AC works with a hot line and a neutral > line; neutral and ground are at the same potential. There should not be > any current flowing through ground. do you know how a neutral is created? just answer this a simple transformer from 230v to 110v, the primary receives a live and a neutral, where is the neutral in the secundary side? > > See http://en.wikipedia.org/wiki/Ground_and_neutral i don't have to see anything, you have, and stop reading that fake encyclopedia
From: david on 8 Jan 2010 07:03 On Fri, 08 Jan 2010 08:05:15 +0000, ArameFarpado rearranged some electrons to say: > Em Sexta 08 Janeiro 2010 01:40, Joe Pfeiffer escreveu: > >> ArameFarpado <a-farpado.spam(a)netcabo.pt> writes: >> >>> Em Quinta 07 Janeiro 2010 08:27, no.top.post(a)gmail.com escreveu: >>> >>>> No, AFAIK the earth-leakage -detector works by measuring the >>>> unbalance between the line and neutral current flow. Since the >>>> unbalance must be returning via the earth. So REMOVING THE EARTH to >>>> the UPS & computer circuit 'eliminates the problem'. But that's a >>>> bodge. One needs to fully understand the problem cause sequence. >>>> . >>>> == TIA. >>> >>> if you have electrical questions, it's better to put them in >>> sci.electronics.basics >>> >>> >>> i can tell you that if you desconnect the earth, ther will be no more >>> a neutral in the output, you will have two live lines with a voltage >>> between them, and that could cause other issues. >> >> You can tell us anything you want, but if you tell us that you're >> wrong. Standard single-phase AC works with a hot line and a neutral >> line; neutral and ground are at the same potential. There should not >> be any current flowing through ground. > > do you know how a neutral is created? > > just answer this > > a simple transformer from 230v to 110v, the primary receives a live and > a neutral, where is the neutral in the secundary side? > > > >> See http://en.wikipedia.org/wiki/Ground_and_neutral > i don't have to see anything, you have, and stop reading that fake > encyclopedia I certainly would not want you to wire my house. Google--> "separately derived source".
From: Joe Pfeiffer on 8 Jan 2010 07:40 ArameFarpado <a-farpado.spam(a)netcabo.pt> writes: > Em Sexta 08 Janeiro 2010 01:40, Joe Pfeiffer escreveu: > >> ArameFarpado <a-farpado.spam(a)netcabo.pt> writes: >> >>> Em Quinta 07 Janeiro 2010 08:27, no.top.post(a)gmail.com escreveu: >>> >>>> No, AFAIK the earth-leakage -detector works by measuring >>>> the unbalance between the line and neutral current flow. >>>> Since the unbalance must be returning via the earth. >>>> So REMOVING THE EARTH to the UPS & computer circuit >>>> 'eliminates the problem'. But that's a bodge. >>>> One needs to fully understand the problem cause >>>> sequence. >>>> . >>>> == TIA. >>> >>> if you have electrical questions, it's better to put them in >>> sci.electronics.basics >>> >>> >>> i can tell you that if you desconnect the earth, ther will be no more a >>> neutral in the output, you will have two live lines with a voltage >>> between them, and that could cause other issues. >> >> You can tell us anything you want, but if you tell us that you're >> wrong. Standard single-phase AC works with a hot line and a neutral >> line; neutral and ground are at the same potential. There should not be >> any current flowing through ground. > > do you know how a neutral is created? The most relevant part of the answer is probably that it's bonded to ground at the service panel. > just answer this > > a simple transformer from 230v to 110v, the primary receives a live and a > neutral, where is the neutral in the secundary side? And the relevance of this to mains wiring is... >> >> See http://en.wikipedia.org/wiki/Ground_and_neutral > i don't have to see anything, you have, and stop reading that fake > encyclopedia The fake encyclopedia bases its answer on the National Electrical Code. Show me a source you regard as more authoritative that disagrees. -- As we enjoy great advantages from the inventions of others, we should be glad of an opportunity to serve others by any invention of ours; and this we should do freely and generously. (Benjamin Franklin)
From: ArameFarpado on 8 Jan 2010 08:17
Em Sexta 08 Janeiro 2010 12:40, Joe Pfeiffer escreveu: > ArameFarpado <a-farpado.spam(a)netcabo.pt> writes: > >> Em Sexta 08 Janeiro 2010 01:40, Joe Pfeiffer escreveu: >> >>> ArameFarpado <a-farpado.spam(a)netcabo.pt> writes: >>> >>>> Em Quinta 07 Janeiro 2010 08:27, no.top.post(a)gmail.com escreveu: >>>> >>>>> No, AFAIK the earth-leakage -detector works by measuring >>>>> the unbalance between the line and neutral current flow. >>>>> Since the unbalance must be returning via the earth. >>>>> So REMOVING THE EARTH to the UPS & computer circuit >>>>> 'eliminates the problem'. But that's a bodge. >>>>> One needs to fully understand the problem cause >>>>> sequence. >>>>> . >>>>> == TIA. >>>> >>>> if you have electrical questions, it's better to put them in >>>> sci.electronics.basics >>>> >>>> >>>> i can tell you that if you desconnect the earth, ther will be no more a >>>> neutral in the output, you will have two live lines with a voltage >>>> between them, and that could cause other issues. >>> >>> You can tell us anything you want, but if you tell us that you're >>> wrong. Standard single-phase AC works with a hot line and a neutral >>> line; neutral and ground are at the same potential. There should not be >>> any current flowing through ground. >> >> do you know how a neutral is created? > > The most relevant part of the answer is probably that it's bonded to > ground at the service panel. correct, it's connected to earth but not by the same connection you have in you house... every house has its own earth connection, the neutral is created by a earth connection in the last transformer of the company that distributes the energy. this is why the neutral may or may not have the same electrical potential as the house's earth. the same way two houses's earth wiring may not have the same potential. anothter question if you don't mind: a lightning bolt falls in the ground at 6 meters from you and a cow, you suffer nothing while the cow gets electricuted and dies... why? > >> just answer this >> >> a simple transformer from 230v to 110v, the primary receives a live and a >> neutral, where is the neutral in the secundary side? > > And the relevance of this to mains wiring is... the output of a ups is not connected to the mains wiring. if the op desconnect the earth wire, he will loose the neutral on the output, if this ups is feeding several machines that could be a problem > >>> >>> See http://en.wikipedia.org/wiki/Ground_and_neutral >> i don't have to see anything, you have, and stop reading that fake >> encyclopedia > > The fake encyclopedia bases its answer on the National Electrical Code. not really, i myself wrote part of a article in wikipedia... anyone qcan wrote articles in there. > Show me a source you regard as more authoritative that disagrees. learn electricity... |