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<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=500105014-25072011>Lars,</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=500105014-25072011></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=500105014-25072011>Scary stuff. I worked with a system similar to this and
went with big wire.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=500105014-25072011></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=500105014-25072011>The problem with xfrms is that you can either have low
standby losses and good efficency at load or vis-a-versa, but you can't really
have both. </SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=500105014-25072011></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT color=#0000ff size=2 face=Arial><SPAN
class=500105014-25072011>Were the xfrms specifically wound for 120x480
conversion? If not, it is possible that the coil taps are connected in
a manner that is not efficient.</SPAN></FONT></DIV>
<DIV><FONT color=#0000ff size=2 face=Arial></FONT> </DIV>
<DIV><SPAN class=500105014-25072011><FONT color=#0000ff size=2 face=Arial>That
being said, 15.6 A @ 120V sound like an awefully large number. Perhaps you
have a bad connection at one of your pull boxes.</FONT></SPAN></DIV>
<DIV><SPAN class=500105014-25072011><FONT color=#0000ff size=2
face=Arial></FONT></SPAN><SPAN class=500105014-25072011><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV><FONT color=#0000ff size=2 face=Arial><SPAN class=500105014-25072011>I
would be happy to stop by and take a look at the xfrm spec etc. with
you.</SPAN></FONT></DIV>
<DIV><BR><SPAN lang=en-us><FONT size=2 face=Arial>Mark Frye</FONT></SPAN>
<BR><SPAN lang=en-us><FONT size=2 face=Arial>Berkeley Solar Electric
Systems</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2 face=Arial>303 Redbud
Way</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2 face=Arial>Nevada
City, CA 95959</FONT></SPAN> <BR><SPAN lang=en-us><FONT size=2
face=Arial>(530) 401-8024</FONT></SPAN> <BR><SPAN lang=en-us></SPAN><A
href="http://www.berkeleysolar.com/"><SPAN lang=en-us><U><FONT color=#0000ff
size=2 face=Arial>www.berkeleysolar.com</FONT></U></SPAN></A><SPAN
lang=en-us><FONT size=2 face=Arial> </FONT></SPAN> </DIV>
<DIV> </DIV><BR>
<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>
<HR tabIndex=-1>
<FONT size=2 face=Tahoma><B>From:</B> re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <B>On Behalf Of </B>lars
Ortegren<BR><B>Sent:</B> Monday, July 25, 2011 7:43 AM<BR><B>To:</B>
re-wrenches@lists.re-wrenches.org<BR><B>Subject:</B> [RE-wrenches] Efficient
step up, down transformers<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV class=WordSection1>
<P class=MsoNormal>Wrenches,<o:p></o:p></P>
<P
class=MsoNormal>
I recently installed three “ultra -efficient” step up-down transformers on an
off grid micro grid project with a 1500’ wire run. The grid is powered by a an
old SW4024(120v) output, stepped up to 480v, and stepped down to 240v at two
locations. I was told by the manufacturer that they were “99% efficient under a
full load”, but upon firing up the system, I found a NO LOAD AMPEREAGE OF 15.6
amps!!! Needless to say, a completely unworkable situation for an off grid
scenario, as the 840ah battery would be drained in a couple of hours before
anything was turned on. I’m wondering if anyone out there has either found off
grid friendly step up-down transformers, or if I’m just screwed and need to pull
parallel 4/0 runs (probably the price of a new car) to fix the problem.
HELP!<o:p></o:p></P>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal><B><I>Lars Ortegren<o:p></o:p></I></B></P>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal><SPAN style="FONT-FAMILY: 'Bodoni MT','serif'">Director of
Operations<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Berlin Sans FB','sans-serif'; COLOR: #002060; FONT-SIZE: 12pt">California
Solar Electric Company<o:p></o:p></SPAN></P>
<P class=MsoNormal>10141 Evening Star Drive, Suite 6<o:p></o:p></P>
<P class=MsoNormal>Grass Valley, CA 95945<o:p></o:p></P>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal>Phone : (530)274-3671<o:p></o:p></P>
<P class=MsoNormal>Fax: (530)274-7518<o:p></o:p></P>
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