<html><body><span style="font-family:Verdana; color:#000000; font-size:10pt;"><div>Check out this link:<br></div><div><br></div><div><a href="http://www.electriciantalk.com/f2/generator-double-delta-1370">http://www.electriciantalk.com/f2/generator-double-delta-1370</a>/ <br></div><div><br></div><div><br>Dan Brown<br>Foxfire Energy Corp.<br>Renewable Energy Systems<br>(802)-483-2564<br><a href="http://www.Foxfire-Energy.com">www.Foxfire-Energy.com</a><br>NABCEP #092907-44</div><div><br><br></div>
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-------- Original Message --------<br>
Subject: Re: [RE-wrenches] Possible genset configuration error...but<br>
how do I convince my client!<br>
From: William Miller <<a href="mailto:william@millersolar.com">william@millersolar.com</a>><br>
Date: Fri, April 08, 2011 1:52 am<br>
To: RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>
<br>
<font size="3">Mick:<br><br> Do you have access to a dual trace oscilloscope? That is how I check phase angle.<br><br> William<br><br> <br> At 09:45 PM 4/7/2011, you wrote:<br> </font><blockquote type="cite" class="cite" cite=""><font size="3">Hello, Mechanics~<br><br> I went to a distant "off grid" jobsite where my client has an inverter/charger system set up for 120/240 60 hz system architecture. While investigating some screwy charge behavior I clipped my "pretty good" Extech clamp meter around the various AC wires from the generator, with the meter set for frequency display. <br><br> The two hots looked good around 60 hz but the neutral was showing wacky frequency numbers much higher...and about double. The ground also showed similar wacky frequency numbers so I think there is a ground fault but my greater worry at present is the approximately double frequency which is showing up on the neutral. <br><br> I suspect that the two hots are not perfectly 180 degrees out of phase to each other, but how do I convince my client of that and how do we fix it?<br><br> The generator is...old...massive...noisy & intimidating of course...and the type with taps that can be set to choose the type of power delivery that one wants. I fear that it may not have taps for good ol' single phase with two opposing hots, however. My client thinks it's set up for something called "double delta" and showed me a diagram that implies this to yield "two hots and a neutral" ordinary single phase. <br><br> The voltage looks normal from each line to neutral and from line to line. It's just that puzzling frequency on the neutral that has me concerned. Charge performance actually cleaned up very well by the time I left the site but I fear that something is still amiss. Gosh! I didn't measure the amps on all lines but if the hots are not canceling each other out maybe the neutral is being required to carry more than just the imbalance current. Maybe I gotta go back and maybe some pointers or suggestions from the group would help me do a better job. Is there anything short of an oscilloscope that can help us figure this out?<br><br> Jolliness,<br><br> Mick Abraham, Proprietor</font></blockquote> <hr>_______________________________________________<br>
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