If I'm following this thread correctly, the
relay is to break the flow of AC current to the
battery based inverter (Outback) from a direct
grid tie inverter when the grid is down and the
batteries are full. The AC coupling here would
be done at the protected loads panel, fed from the AC Out of the Outback.
We are having problems breaking the AC from
direct grid tie inverters feeding directly into
the grid. When the relays open, the breakers
that the inverters feed into, trip. They don't
always trip, but trip randomly.
The relays are open frame, similar to the ones
you describe below. Why are we having this
problem, as it seems that what we are doing is common practice?
Thanks for your help.
Drake
I have usually done the same setup as Kirk but
I have used the Potter Brumfield PRD style
relay which are available from Grainger under
the Dayton brand name (of course). These
provide a visual break which is nice to be
able to check when doing testing etc.
I like using the AC coil together with a DC coil
signal relay as it allows some nice options for
redundancy and fail-safe design.
These are large, heavy duty, open frame 30 amp 2
pole with normally closed and normally open
contacts and available with 12vdc, 24vdc, 120vac
or 240vac coils. Grainger even has one now with
an auxiliary switch included which could be
used to send a signal or turn on a light to
alert the system user that there is an outage.
Relays: http://www.grainger.com/Grainger/wwg/catalogPDF.shtml
NEMA 1 Type Relay Enclosure: http://www.grainger.com/Grainger/items/1EGH7
I hope this helps!
Christopher
Christopher Freitas
Director of Research and Development
OutBack Power Systems, Inc.
<mailto:cfrei...@outbackpower.com>cfrei...@outbackpower.com
Tel 360 435 6030
Cell 360 202 4239
19009 62nd Ave NE
Arlington WA 98223 USA
<http://www.outbackpower.com/>www.outbackpower.com
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org]
On Behalf Of Kirk Herander, VSE
Sent: Wednesday, June 03, 2009 11:05 AM
To: jry...@netscape.com; 'RE-wrenches'
Subject: Re: [RE-wrenches] AC coupled relay
I have done it with a SQD 60a, 240 vac
contactor. The coil is 120 vac. It is driven by
a secondary 12vdc relay sending 120 ac to the
coil. The coil of the dc relay is driven by the
12 vdc auxiliary output of the Outback FX
inverter. I use the contactor and dc relay
normally closed contacts. They open when the inverter energizes the dc relay.
Kirk Herander
Vermont Solar Engineering
802.863.1202
NABCEP(tm) Certified Solar Installer
NYSERDA-eligible Installer
VT Solar Incentive Program Partner
----------
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jeff Yago
Sent: Wednesday, June 03, 2009 9:35 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] AC coupled relay
What specific supplier, model number, and brand
relay have you found to be perfect to isolate
the inverter AC output to the sub-panel of a
battery-based inverter in an AC coupled system?
This will be in the 20 to 30 amp 240 VAC contact
range. Also, do you normally set it up as N.C.
or N.O. for fail-safe reasons? Coil voltage 12 vdc or 120 vac?
Thanks,
Jeff Yago
Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
NABCEP Certified PV Installer TM
Office - 740-448-7328
Mobile - 740-856-9648
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