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<div class="moz-cite-prefix">On 5/30/2016 1:48 PM, Jeremy Rodriguez
wrote:<br>
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<div>Bob</div>
<div id="AppleMailSignature">Can you elaborate a little on this
extension cord idea either here or off-line? Thank you<br>
</div>
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<br>
<br>
Sure. The extension cord, in this case, is just added resistance.
Some inductance but<br>
mainly resistance. The current from the starting load is reduced by
the voltage being<br>
dropped along the cable. So instead of the SW sourcing quite as
much current, it sees<br>
less current but some power is dissipated along the extension cord.
Way more power<br>
at high surge of course since power (Watts) is current squared times
cable resistance.<br>
If the startup current doubles, then the power dissipated in the
cord quadruples<br>
during that surge time.<br>
<br>
This less current drawn from the SW inverter allows the voltage at
the motor to<br>
drop as was mentioned and the Over Current Protection (OCP) inside
the SW does<br>
not get activated (hopefully) and the output voltage does not go to
zero.<br>
<br>
Since the motor startup is fairly short, there isn't much lost
energy in the cord.<br>
<br>
Also, since the cable is sort of long-ish, the power dissipated is
fairly nicely spread out<br>
along the cord and no one spot gets hot, except maybe the plug.<br>
<br>
You could also just add longer real wire or a resistor. Fun Ohm's
law stuff.<br>
<br>
boB<br>
<br>
<br>
<br>
<br>
<br>
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<div id="AppleMailSignature">
<br>
Jeremy Rodriguez
<div>Solar Installation And Design Expert <br>
<div>All Solar, Inc.
<div>1463 M St<br>
<div>Penrose Colorado 81240</div>
<div><br>
</div>
<div>Sent by Jeremy's iPhone. Sorry for typos and
shorthand!</div>
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<div><br>
On May 30, 2016, at 1:15 PM, "<a moz-do-not-send="true"
href="mailto:bob@midnitesolar.com">bob@midnitesolar.com</a>"
<<a moz-do-not-send="true" href="mailto:bob@midnitesolar.com">bob@midnitesolar.com</a>>
wrote:<br>
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<p><br>
</p>
<p>The (newer) SW5548 was harder on over current protection,
mainly because</p>
<p>it could put out more current than the SW4048... <br>
</p>
<p>One trick to try is to place a long(ish) extension cord
between the SW and the load to give it a wee bit of series
resistance.</p>
<p>Doing this would often reduce that OCP and help motors to
start.<br>
</p>
<p>boB<br>
</p>
<br>
<div class="moz-cite-prefix">On 5/30/2016 11:03 AM, Dan Fink
wrote:<br>
</div>
<blockquote
cite="mid:CAF+3Lncg+BzMN86GdqgM7eyK8DDWB6EMqAd7VEyJiSBD8nZquA@mail.gmail.com"
type="cite">
<div dir="ltr">Does your air compressor have an unloader
valve, or can you install one?
<div>That should do the trick, sounds like you are just
running into the regular high surge current demand.</div>
<div>Off the grid, compressors are in about the same nasty
league as old well pumps as far as surge demand.</div>
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<div><span
style="font-size:12.8000001907349px">Dan
Fink</span>
<div
style="font-size:12.8000001907349px">Adjunct
Professor of Solar Energy
Technology, Ecotech Institute</div>
<div
style="font-size:12.8000001907349px">IREC
Certified Instructor™ for: </div>
<div
style="font-size:12.8000001907349px">~
PV Installation Professional</div>
<div
style="font-size:12.8000001907349px">~
Small Wind Installer</div>
<div
style="font-size:12.8000001907349px">Executive
Director, Buckville Energy</div>
<div
style="font-size:12.8000001907349px">NABCEP
Registered Continuing Education
Providers™<br>
<a moz-do-not-send="true"
href="tel:970.672.4342"
value="+19706724342"
style="color:rgb(17,85,204)"
target="_blank">970.672.4342</a></div>
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<div class="gmail_quote">On Mon, May 30, 2016 at 10:46 AM,
Jeremy Rodriguez <span dir="ltr">
<<a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:allsolarjeremy@msn.com">allsolarjeremy@msn.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
Hello<br>
I've got an SW+5548 that will barley start my air
compressor. Once it does run it shows 17 Amps on the
inverters loads meter. During start up it reads 60+
amps.<br>
Do you think better capacitors would help the
situation?<br>
BTW I've never ran the compressor off grid prior.<br>
I even tried #8 from the Breaker to the pressure
switch, about 9ft, with no benefit. The compressor
will only start with the tank completely empty.<br>
<br>
Jeremy Rodriguez<br>
Solar Installation And Design Expert<br>
All Solar, Inc.<br>
1463 M St<br>
Penrose Colorado 81240<br>
<br>
Sent by Jeremy's iPhone. Sorry for typos and
shorthand!<br>
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