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Article #258Re: Two phases to house - loss of neutral
From: David
Date: Sat, 28 Nov 2009 00:28
Date: Sat, 28 Nov 2009 00:28
29 lines
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2376 bytes
Sylvia Else wrote: > > Anyway, all a test would do is show that the answer is probably correct. > It wouldn't make it any more obvious. > > Sylvia. Sylvia, Draw yourself a vector diagram. Then with some simple trigonometry it *should* be more obvious. Assume a resistive load between two of the three phases, with a load of 1 unit current and 1 unit voltage. The load will thus be 1 unit power. Each single phase meter will see the in phase voltage as 1 / sqrt(3) (240/415). Each single phase meter will see an in phase current of 1 x cos(30). Remember that cos(30) = 1/2 sqrt(3). This gives the power measured by each meter as V*I = 1/sqrt(3) * 1/2 sqrt(3) The two square roots of three cancel, which, unsurprisingly leaves 1/2. Thus each meter records 1/2 the power in the load, and you will thus get billed correctly. David
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X-Google-Thread: a5a6238865,dcb8eebd9233b785 X-Google-Attributes: gida5a6238865,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news1.google.com!news1.google.com!npeer01.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!nx01.iad01.newshosting.com!newshosting.com!news.astraweb.com!border1.newsrouter.astraweb.com!not-for-mail Date: Sat, 28 Nov 2009 11:28:08 +1100 From: David <david@usenet.com> User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 Newsgroups: sci.electronics.repair,aus.electronics Subject: Re: Two phases to house - loss of neutral References: <0083b31e$0$1587$c3e8da3@news.astraweb.com> <006c3c5f$0$8071$c3e8da3@news.astraweb.com> <7n71olF3h6pbiU4@mid.individual.net> <7n764tF3kuc7fU1@mid.individual.net> <hem69m$imk$2@news.eternal-september.org> <006d4f21$0$16824$c3e8da3@news.astraweb.com> <5acug5p9kitc61qk38ln5su9jv3vcqsupv@4ax.com> <008083db$0$8069$c3e8da3@news.astraweb.com> <4b0f9372$1@dnews.tpgi.com.au> <006df466$0$8169$c3e8da3@news.astraweb.com> In-Reply-To: <006df466$0$8169$c3e8da3@news.astraweb.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 30 Message-ID: <0158ed2f$0$3197$c3e8da3@news.astraweb.com> Organization: Unlimited download news at news.astraweb.com NNTP-Posting-Host: fd601f44.news.astraweb.com X-Trace: DXC=WoE]DJWeNc:4K?0c7HD\@7L?0kYOcDh@:9[TW:2INN;4hAfM2O2Xca?fDWggLhQA41X:OnX2bL_H1V9InOV2bc=1