# [rescue] SGI Challenge L systems available in Denver

Fri Sep 17 13:40:22 CDT 2004

```" From: Francisco Javier Mesa-Martinez <lefa at ucsc.edu>
"
" On Fri, 17 Sep 2004, Sandwich Maker wrote:
"
" > " From: patrick at mail.zill.net (Patrick Giagnocavo)
" > "
" > " On Fri, Sep 17, 2004 at 10:57:00AM -0400, Nathan Raymond wrote:
" > " >
" > " > What's really needed is a large AC->DC converter in the basement and new
" > " > DC outlets alongside AC outlets in houses, and devices that work with the
" > " > []
" > "
" > " I was doing some reading on solar power, and this is a hot topic in
" > " that community.  Basically where feasible run DC straight from the
" > " battery bank, only using AC where necessary.
" > "
" > " The problem with DC is its perceived danger, and that you need thicker
" > " wires for running large loads.
" >
" > depends on the voltage.  110vdc doesn't need any thicker wires than
" > 110vac, but i assume you must mean 12vdc.
"
" The thickness of the wire has nothing to do with the voltage differential,
" you could have 1000V on a hair thin wire: It is them Amps that matter :)
" Electrical energy losses are directly proportional to current flow, not to
" the energy flow.

yes yes yes...  i was assuming that since we were talking relative to
statement 'you need thicker wires for running large loads' than with
ac is the assumption that you'll be running at lower voltage, right?]

" The reason for using AC is very simple: It is easier to genreate alternate
" current, and AC can be easily stepped up or down. The low voltage/ hight
" current generated can be stepped up to high voltage/low current for
" transmission (lower loss when the current is smaller), and then it can be
" stepped back to low voltage/high current at the destination point. Plus
" you can also play with the phase in order to adapt for long distance
" distribution, something that can not be done with DC.

yes, westinghouse won because ac greatly simplifies the
infrastructure, and tesla's invention of the alternator et al put his
system over the top.

but phase doesn't matter in dc - and the latest long-distance
transmission lines are dc, because inductive and radiative losses
losses are significant over hundreds of miles and hundreds of
kilovolts.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen

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