Re: dc-ac inverter

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Virtualgod" <mike.marcum-at-zoomtown-dot-com> 

Found a cheap sourse of goodies at work (a Crisco bottling plant) since they
are upgrading/doing various maintenance. Some of this stuff (various
transformers, motors, some stuff I can't identify yet,etc) is perfctly fine
other than the fact it uses 440/480v. The rest I'm stripping for what I can
use (like an old elevator control board, have no elevator, but could use the
load caps/relays). My whole apartment runs on a 120v,30A breaker (I actually
cheated and pulled out the 20A when I first moved in). With 480v, I'd only
have 7.5A, good to run a smallish motor/transformer, but not my x-ray tranny
when get it potted (have to take some measurements to see what the primary
voltage is supposed to be, I'm thinking 440 or so since the primary wire is
something like 4 awg or so.
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, April 04, 2004 3:00 PM
Subject: Re: dc-ac inverter


 > Original poster: Sean Taylor <sstaylor-at-uiuc.edu>
 >
 >
 > >I'd look into the inverters and such aimed at the home power market,
since
 > >they'll have the capacities and sine wave output.
 > >You could also use a 20 kW 240V inverter and run it into a 240:480V dry
 > >transformer.
 >
 >
 > Don't have to look at ones just for the home market - there are plenty of
 > high power units for marine use and R/V type use that are pure sine wave.
 > I would agree with the 240:480 transformer bit - much easier to do, but it
 > really depends on the application - which brings me to my question:  what
 > do you need 480VAC for, and why from batteries/inverter?  What's wrong
with
 > getting a step-up transformer and "making" 480 from the utility
 > power?  That would be a pretty good sine wave, and wouldn't require lots
of
 > batteries either.  BTW, the multiple inverter in series thing would work
IF
 > you could get the frequency generating portion from one to run them all so
 > that they would be in phase all the time.  You would also have to lift the
 > grounds so that the secondaries of the transformers would all be
 > isolated.  A relatively common method for many smaller inverters now is to
 > use a HF drive for the transformer, and use higher voltage semis on the HV
 > side to shape the waveform to 60 Hz which yields much less iron and a
 > lighter inverter.
 >
 > Sean Taylor
 > Urbana, IL
 >
 >
 >