On 6/30/2011 8:35 PM, Nick Vida wrote:
Hi wrenches.
I had an interesting case today that I have been thinking about since
it happened. I dont have all the details because the homeownter had to
leave before I was done with the service call, but here is what I do
know. SB5000 with 2 strings of 15 modules. String one was 437 vdc, and
string 2 was 247vdc. I decided to look for a ground fault, and I
turned off the inverter. I measured for ground faults and found no
evidence of anything wrong in that regard. As the homeowner was out of
time and wanted me to go, I re-landed the wires in the dc disco, and
when I replaced the fuses, I noticed a minor arc when one of the fuses
was going it. Although I had no time to measure it, I think that there
might be a partial short circuit, possibly with one complete string
and some panels of the other string, and the remaining panels on the
second string. My mind was racing with how I could have measured for a
partial short circuit without seeing it as an arch. I can imagine such
a thing on a bigger system being a dramatic electrical event.
needless to say, I cant wait to get back there and go through the
signal path properly and find out what the electrician did. And of
course i realized that replacing the fuses in such a questionable
situation was probably not the best idea.
Do any of you have any thoughts on how one would measure for such a thing?
nick vida
What does this part of your question mean ??
"I noticed a minor arc when one of the fuses was going it."
boB
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