<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">It's possible, depending on the transformer construction.<br><br>We've evaluated transformers that are spec'd up to 99% efficient,<br>but these were special transformers.<br><br>I don't know what type of transformer Lars was considering.<br><br><br>Dan<br><br><br>--- On <b>Mon, 7/25/11, Dana <i><dana@solarwork.com></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: Dana <dana@solarwork.com><br>Subject: Re: [RE-wrenches] Efficient step up, down transformers<br>To: "'RE-wrenches'" <re-wrenches@lists.re-wrenches.org><br>Date: Monday, July 25, 2011, 10:16 AM<br><br><div id="yiv180767051"><style><!--
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--></style><div class="yiv180767051WordSection1"><p class="yiv180767051MsoNormal"><span style="font-size: 14pt; font-family: "sans-serif";">Seriously I have never heard of 99% eff. under load with a transformer. Anyone else heard of this kind of eff. factor?</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 14pt; font-family: "sans-serif";"> </span></p><div><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">Dana Orzel</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">Great Solar Works, Inc</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">E - dana@solarwork.com</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">V - 970.626.5253</span></p><p class="yiv180767051MsoNormal"><span
style="font-size: 12pt; font-family: "sans-serif";">F - 970.626.4140</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">C - 970.209.4076</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">web - www.solarwork.com</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";"> </span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">"Responsible Technologies for Responsible People since 1988"</span></p><p class="yiv180767051MsoNormal"><span style="font-size: 12pt; font-family: "sans-serif";">Do not ever believe anything, but seriously trust through action.</span></p></div><p class="yiv180767051MsoNormal"><span style="font-size: 14pt; font-family: "sans-serif";"> </span></p><div><div
style="border-right: medium none; border-width: 1pt medium medium; border-style: solid none none; border-color: rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color; padding: 3pt 0in 0in;"><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><b><span style="font-size: 10pt; font-family: "sans-serif";">From:</span></b><span style="font-size: 10pt; font-family: "sans-serif";"> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Mark Frye<br><b>Sent:</b> Monday, July 25, 2011 9:11 AM<br><b>To:</b> 'RE-wrenches'<br><b>Subject:</b> Re: [RE-wrenches] Efficient step up, down transformers</span></p></div></div><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"> </p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: blue;">Lars,</span><span style="font-size: 12pt;
font-family: "serif";"></span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"> </span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: blue;">Scary stuff. I worked with a system similar to this and went with big wire.</span><span style="font-size: 12pt; font-family: "serif";"></span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"> </span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: blue;">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><span style="font-size: 12pt; font-family:
"serif";"></span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"> </span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: blue;">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><span style="font-size: 12pt; font-family: "serif";"></span></p><div><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"> </span></p></div><div><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: blue;">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.</span><span style="font-size: 12pt; font-family: "serif";"></span></p></div><div><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"> </span></p></div><div><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: blue;">I would be happy to stop by and take a look at the xfrm spec etc. with you.</span><span style="font-size: 12pt; font-family: "serif";"></span></p></div><div><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"><br></span><span style="font-size: 10pt; font-family: "sans-serif";">Mark Frye</span><span style="font-size: 12pt; font-family: "serif";"> <br></span><span style="font-size: 10pt; font-family: "sans-serif";">Berkeley Solar Electric
Systems</span><span style="font-size: 12pt; font-family: "serif";"> <br></span><span style="font-size: 10pt; font-family: "sans-serif";">303 Redbud Way</span><span style="font-size: 12pt; font-family: "serif";"> <br></span><span style="font-size: 10pt; font-family: "sans-serif";">Nevada City, CA 95959</span><span style="font-size: 12pt; font-family: "serif";"> <br></span><span style="font-size: 10pt; font-family: "sans-serif";">(530) 401-8024</span><span style="font-size: 12pt; font-family: "serif";"> <br><a rel="nofollow" target="_blank" href="http://www.berkeleysolar.com/"><span style="font-size: 10pt; font-family: "sans-serif";">www.berkeleysolar.com</span></a></span><span style="font-size: 10pt; font-family: "sans-serif";"> </span><span style="font-size: 12pt; font-family: "serif";"> </span></p></div><div><p class="yiv180767051MsoNormal"
style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"> </span></p></div><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "serif";"> </span></p><div class="yiv180767051MsoNormal" style="margin-left: 0.5in; text-align: center;" align="center"><span style="font-size: 12pt; font-family: "serif";"><hr align="center" size="3" width="100%"></span></div><p class="yiv180767051MsoNormal" style="margin-right: 0in; margin-bottom: 12pt; margin-left: 0.5in;"><b><span style="font-size: 10pt; font-family: "sans-serif";">From:</span></b><span style="font-size: 10pt; font-family: "sans-serif";"> 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</span><span style="font-size: 12pt; font-family: "serif";"></span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;">Wrenches,</p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"> 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!</p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"> </p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><b><i>Lars Ortegren</i></b></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"> </p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-family: "Bodoni MT";">Director of Operations</span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 12pt; font-family: "Berlin Sans FB"; color: rgb(0, 32, 96);">California Solar Electric Company</span></p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;">10141 Evening Star Drive, Suite 6</p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;">Grass Valley, CA 95945</p><p
class="yiv180767051MsoNormal" style="margin-left: 0.5in;"> </p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;">Phone : (530)274-3671</p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;">Fax: (530)274-7518</p><p class="yiv180767051MsoNormal" style="margin-left: 0.5in;"> </p></div></div><br>-----Inline Attachment Follows-----<br><br><div class="plainMail">_______________________________________________<br>List sponsored by Home Power magazine<br><br>List Address: <a ymailto="mailto:RE-wrenches@lists.re-wrenches.org" href="/mc/compose?to=RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Options & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br><br>List-Archive: <a href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org"
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