Article View: sci.electronics.repair
Article #88Re: is third transformer hole an earth?
From: ian field
Date: Wed, 12 Nov 2008 19:01
Date: Wed, 12 Nov 2008 19:01
79 lines
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5220 bytes
"Whiskers" <catwheezel@operamail.com> wrote in message news:slrnghlo20.bmt.catwheezel@ID-107770.user.individual.net... > On 2008-11-12, Arfa Daily <arfa.daily@ntlworld.com> wrote: >> >> "Whiskers" <catwheezel@operamail.com> wrote in message >> news:slrnghjjbg.e5j.catwheezel@ID-107770.user.individual.net... >>> On 2008-11-11, Arfa Daily <arfa.daily@ntlworld.com> wrote: >>>> "Whiskers" <catwheezel@operamail.com> wrote in message >>>> news:slrnghja8j.e5j.catwheezel@ID-107770.user.individual.net... >>>>> On 2008-11-10, Dave Plowman (News) <dave@davenoise.co.uk> wrote: >>>>>> In article <slrnghhb1o.bes.catwheezel@ID-107770.user.individual.net>, >>>>>> Whiskers <catwheezel@operamail.com> wrote: >>> >>> [...] >>> >>>> A system carrying a lot of amps to the load that's drawing it, is no >>>> more >>>> or >>>> less dangerous than one that's only carrying a small current, except in >>>> as >>>> much as there is a greater potential for heat failure at connection >>>> points >>>> within that system. A high voltage system, irrespective of how many >>>> amps >>>> it >>>> is capable of carrying above a few milliamps, is far more dangerous to >>>> a >>>> human, than a low voltage system good for a few hundred amps. Given the >>>> (reasonably) constant resistance of any described path through the >>>> human >>>> body, a voltage of a hundred volts with a current availability of as >>>> little >>>> as 50mA, may be enough to kill under the right (wrong!) circumstances. >>> >>> So a charge of 10kV from walking across a carpet (DC) , or a >>> "non-lethal" >>> 50kV "Tazer" (AC), are more dangerous than a 1kV power line? The danger >>> from 'High Voltage' power lines comes from the vast amount of current >>> they >>> can deliver. >> >> You see, there you go getting your apples and oranges mixed up again. A >> static charge from a carpet is not lethal to you because it is an >> extremely >> high resistance source. That is the nature of a static charge. No matter >> whether it is 1kV, 10kV or 40kV, the source resistance will ensure that >> only >> uA will flow for decimals of a uS. Enough to give you a nasty little >> crack, >> yes, but not enough to come within several orders of magnitude of being >> lethal. The same applies to the taser. It is designed to not be able to >> supply enough current (theoretically) to be lethal. However, its aim is >> to >> incapacitate by disrupting nerve activity and causing extreme pain. To do >> this, the charge is applied to the receiving body in multiple >> short-duration >> pulses. In some cases, this has proven to be fatal, I believe, due to the >> length of time that the pulses are delivered for. On the other hand, a >> high >> voltage power line, or even a fairly low voltage household supply, *is* >> potentially lethal not because it can deliver huge amounts of amps, but >> because the voltage that is present, is sufficient to drive *enough* >> (mili) >> amps from that low resistance source through the conduction path within >> the >> body. > > Precisely; it isn't the voltage that's lethal, it's the current. If the > current isn't available, the voltage is pretty harmless. High-voltage > mains power lines carry a /lot/ of current, whereas high-voltage 'Tazers' > don't. > In that case you shouldn't have any problem grabbing the high voltage terminal of a 2kV microwave oven transformer - its only rated for 500mA. On the bright side, we wouldn't have to put up with you talking complete and utter bollox.
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X-Google-Thread: 1131b0,8ae7935e94fea1ee X-Google-Thread: faa3c,8ae7935e94fea1ee X-Google-Attributes: gid1131b0,gidfaa3c,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news2.google.com!news1.google.com!news.glorb.com!eweka.nl!hq-usenetpeers.eweka.nl!cyclone03.ams.highwinds-media.com!news.highwinds-media.com!npeersf02.ams.highwinds-media.com!newsfe21.ams2.POSTED!7564ea0f!not-for-mail From: "ian field" <gangprobing.alien@ntlworld.com> Newsgroups: sci.electronics.repair,24hoursupport.helpdesk References: <gf43nr$fiv$1@registered.motzarella.org> <5JkRk.106$Cn3.92@newsfe20.iad> <slrnghc3uf.bnl.catwheezel@ID-107770.user.individual.net> <op.uke2nuxb4buhsv@fx62.mshome.net> <slrnghhb1o.bes.catwheezel@ID-107770.user.individual.net> <4ffc47586adave@davenoise.co.uk> <slrnghja8j.e5j.catwheezel@ID-107770.user.individual.net> <U3jSk.85501$i%.83610@newsfe25.ams2> <slrnghjjbg.e5j.catwheezel@ID-107770.user.individual.net> <7qrSk.8445$ji.2138@newsfe27.ams2> <slrnghlo20.bmt.catwheezel@ID-107770.user.individual.net> Subject: Re: is third transformer hole an earth? Lines: 81 X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 X-RFC2646: Format=Flowed; Original X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Message-ID: <lKFSk.63168$b76.12947@newsfe21.ams2> NNTP-Posting-Host: 81.105.200.30 X-Complaints-To: http://netreport.virginmedia.com X-Trace: newsfe21.ams2 1226516497 81.105.200.30 (Wed, 12 Nov 2008 19:01:37 UTC) NNTP-Posting-Date: Wed, 12 Nov 2008 19:01:37 UTC Organization: virginmedia.com Date: Wed, 12 Nov 2008 19:01:22 -0000