-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 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. 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). 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. H -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFE3Ew5/3QXwQQkZYwRAlYaAJsGe3RCLAgWO6knje/rWXwD6S0irQCfcgsO bkdH6utTMuvNYMUJ+5mEJmc= =/bVW -----END PGP SIGNATURE----- -- gentoo-user@gentoo.org mailing list
