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<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>
<blockquote type=cite class=cite cite>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></body>
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