[RE-wrenches] AC coupled relay

[Drake Chamberlin]

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:cfreitas at outbackpower.com>cfreitas at 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-bounces at lists.re-wrenches.org 
>[mailto:re-wrenches-bounces at lists.re-wrenches.org] 
>On Behalf Of Kirk Herander, VSE
>Sent: Wednesday, June 03, 2009 11:05 AM
>To: jryago at 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-bounces at lists.re-wrenches.org 
>[mailto:re-wrenches-bounces at 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  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20090603/790ed625/attachment-0004.html>