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