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On Friday 11 August 2006 11:22, Hamish Marson wrote: |
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> Dale wrote: |
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> > Mike Williams wrote: |
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> >> On Thursday 03 August 2006 19:27, James wrote: |
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> >>> The simplist solution is NOBODY puts a 240 VAC power supply |
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> >>> into a computer unless it's going to draw some serious current |
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> >>> (amps) thus by the nature of it being 240 VAC, you already know |
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> >>> it is a power hog. |
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> >> |
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> >> Now, I'm not electrical engineer, but I know my way around a fuse |
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> >> board and electricity having fitted out both our new offices for |
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> >> power, network, and some walls. |
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> >> |
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> >> In the UK, and most (if not all) of Europe, Africa, and Asia too, |
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> >> run on about 240 volts, 230 +-10% I think now. Pretty much the |
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> >> whole world, except the Americas. |
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> > |
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> > Well, the USA has the same coming in too. We have 220v to 240v |
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> > coming in but that is split into different legs for the 110v to |
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> > 120v stuff. |
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> |
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> Unless those two legs are in phase, you're still only getting |
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> 110V-120V AC. IIRC (And it's from 20 years ago I'm working here) it's |
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> not, it's just two legs of the 3 phase generated power. Which means |
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> they're 120 deg out of phase, and so you still only get 110-120V. In |
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> order to get 220-240V, you'd need 3 phase power. |
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|
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Safer to use a transformer 110V-220V which will lessen the danger of |
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playing with two or three live wires, a misconnection can cause an |
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outage with all sorts of problems generated, died disks and other |
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apparatus. |
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|
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> I suspect you get two 110V lines because of current limitations. Not |
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> to provide you with 220V which you'r enot going to get from just |
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> adding two out of phase lines. (Unless of course the US has wired up |
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> two in-phase separate 110V lines. In which case you can get 220V |
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> outof it, but I seem to remember a lecture in Eng Sci saying it was |
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> common to take 2 of 3 phases to a house in the US & alternate which 2 |
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> between successive houses. |
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> |
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> > If you are using transformers to reduce it from 220v to 110v, that |
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> > will waste some energy right there. Transformers are not real |
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> > efficient. If you touch it and it is warm, that is what you are |
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> > wasting. That will also make whatever you are cooling with work |
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> > harder too. |
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> |
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> Plus you need twice the current at 110V vs 220V. (Volts are big 'V' |
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> BTW! Named after Voltaire). |
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|
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Sorry, the french writer Voltaire was not dabbling in science. It was |
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Alessandro Guiseppe Antonio Volta who detected the reaction of |
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different metals on the muscles of a hindlegs of a frog and build the |
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first electric battery from that detection. |
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|
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> This means higher line losses as loss is proportional to current. |
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> Higher line losses mean that cable length becomes more of a problem. |
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> (A 10V drop in 240V is less than 5%. 10V drop in 120V is almost 10%. |
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> Much more significant). |
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> |
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> All-in-all I prefer 240V single phase. |
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> |
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|
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So do I, although in itself that voltage is deadly |
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-- |
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Herman Grootaers |
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-- |
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