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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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>> |
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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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>> |
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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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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 outof |
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it, but I seem to remember a lecture in Eng Sci saying it was common |
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to take 2 of 3 phases to a house in the US & alternate which 2 between |
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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). This means higher line losses as loss is |
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proportional to current. Higher line losses mean that cable length |
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becomes more of a problem. (A 10V drop in 240V is less than 5%. 10V |
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drop in 120V is almost 10%. Much more significant). |
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All-in-all I prefer 240V single phase. |
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H |
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