On 29 Sep 2007 13:45:41 GMT, phil-news-nospam@ipal.net
wrote:

<snip>


>Because power supplies actually convert the
>voltage UP to around this level first, before converting back down to the
>voltages the mainboard and devices use, a smaller more efficient power
>supply could be used in each machine when the source voltage is in this
>range.

The difference would be negligible, when a PSU uses a
roughly 360VDC input to the chopper transistors it is merely
a bridge rectifier followed by capacitors. Active PFC units
have to maintain a level above the peak rectified DC so 360V
wouldn't be enough margin. The PSU will still need
capacitor(s) for this 360V so the only thing removed would
be the bridge rectifier, roughly 1% efficiency difference
and practically no difference in PSU size.

Further, commodity grade electrical supply line wire is not
very expensive relative to most other components, the loss
on the (existing AC, or per your idea going to DC) supply
wiring is also negligible.


>But such a setup would be far too hazardous for typical home use
>(that is, not something sold commercially for a consumer market, even
>though an engineer hobbyist might have no problem with it).


It would be impractical and expensive, but the hazard not
significantly different than present 110/220V AC delivery
systems. All that to save a trivial amount of power.