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<font size=3>Dick:<br><br>
Thanks for the reply. To clarify, we have tried his with one
transformer and with two transformers. Our success rate is lower
powering one transformer. My hunch is that the capacitance of the
feeder is buffering...<br><br>
I wonder if I use a large solid state relay with zero crossing switching
I might have better luck.<br><br>
<br>
William Miller<br><br>
<br>
At 06:23 PM 5/12/2010, Richard L Ratico wrote:<br>
<blockquote type=cite class=cite cite>Bill,<br>
Your branch circuit breaker is pretty small.<br>
Are you energizing both transformers simultaneously? If so, it might help
to<br>
energize them individually.<br><br>
The branch breaker can be up to 250% of the step up transformer's
primary<br>
rating. 10kVA/240V=41A.<br>
41A x 2.5=100A. (round numbers). To do this you would also need
overcurrent<br>
protection on the transformer secondary. <br><br>
Of course, you've already got the 100A main tripping. That's why I asked
if<br>
you're<br>
energizing them simultaneously. <br><br>
Transformer inrush can be a real problem. <br><br>
Hope this helps.<br><br>
Dick Ratico<br>
Solarwind Electric <br><br>
--- You wrote:<br>
Friends:<br><br>
I have on off-grid client that is trying to eliminate winter generator
run <br>
time. He has a rental on another corner of the property that has
grid <br>
power. When it was installed, he put in an extra meter, hoping to
use it <br>
to run a utility back up feeder to charge batteries.<br><br>
We are now installing this feeder. We purchased two 10KVA 240/600
volt <br>
transformers to bump the voltage to 600 and then back down to
120/240.<br><br>
Here's the problem: when we energize the circuit breaker that feeds
the <br>
transformer, the circuit breaker AND the main breaker trip. The
<br>
transformer is 10KVA, the main is 100 amps and the branch breaker is
<br>
60A. The breakers hold sometimes but trip other times. This
is obviously <br>
an inrush problem. How do I correct this problem?<br><br>
Thanks in advance,</font></blockquote></body>
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