I think we can do this. Each does have its own neutral, (we added one).
Outback didn't mention this possibility. It's definitely worth a shot.
We only have an one hour window to work on this in any one day do to the
operation of the facility. Thank you. Chris
On 11/28/2012 11:56 PM, Philip wrote:
We had exactly this scenario at Dankoff Solar, to back up all the computer loads in the
business. The building was 120/208, and the two SW inverters would sync to their
respective phases, 120 degrees apart. The fun part was watching them on a scope when you
shut off grid power -- they would drift to 180 degrees over a ten count. Reconnect AC
input, and they'd readjust back to 120 degrees and latch to grid. This was with or
without the stacking cable, BTW. The SW didn't really stack together, as much as it
stacked apart. The stacking cable primarily sent a timing signal to tell the other
inverter to be in opposition. There was also some communication on charging, etc, but it
was pretty rudimentary as far as "coordination" went.
The trick is that you can only feed 120v loads, and each phase needs its own
neutral (or neutral MUST be sized for 2x inverter capacity).
Since the original system didn't and shouldn't have multi-phase loads, this can also work
with the OutBack GT3048 inverters. However, you will need to unplug one from the Hub,
program both as Masters, and should also disable charging on that single inverter. The
inverter on the hub with the charge controllers will be the "master" of the
system, the other will just help sell power to the grid in normal circumstances, and
power loads on its output when the grid is down.
Phil
On Nov 28, 2012, at 10:06 AM, Christopher Warfel
<cwar...@entech-engineering.com> wrote:
We were asked to replace two failed Trace SW4048 inverters with two Outback
GT3048 inverters. Upon start up the slave inverter would not connect. We did
not realize that the building service is 208, 3 phase. The bypass is 120/240
which the SW4048s could connect to without a problem. Outback says their
inverters will not connect to this system because of the phase angle of 120 and
their software.
The phases are always going to be at this rotation, so I don't see a
transformer helping solve the problem, but this is something I am really
unfamiliar with.
So the input at the inverter panel is two 120 volt phase at 120 degrees. The
output to the EP is 120/240.
I am asking if anyone has an idea of how to fix this problem? The goal is to
have a grid interconnected system with battery backup.
Chris
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
--
Christopher Warfel, P.E.
ENTECH Engineering, Inc.
Energy Utilization Experts
(401)466-8978
The information contained within this communication shall
be considered confidential and shall not be retransmitted
without knowledge of the sender. Please contact us if
this email reached you in error. Thank you.
_______________________________________________
List sponsored by Home Power magazine
List Address: RE-wrenches@lists.re-wrenches.org
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
