How close is the transfer panel from the main panel? If the distance is not to far then actuate the relay (nc) from the generator source NOT the utility. Generator running the relay is opened, only need to switch one leg of the SMA stuff as the reduced input voltage would keep it from connecting.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Kelly Keilwitz, Whidbey Sun & Wind Sent: Thursday, November 20, 2008 12:31 PM To: RE Wrenches listserve Subject: Re: [RE-wrenches] grid-tie inverters & generators Jay, Drake, Don, Jeff & Wrenches, The relay seems like a reasonable solution. However, if the main panel is entirely backed up by the genny, to power the relay from the grid (only) requires a line-side tap, yes? Is there a simple solution that I¹m missing? We have another, similar system completed, just waiting for 2009 to commission. So, I'd like to know if it's really needed, and the best procedure, before investing the time and cost to go back. There must be many Wrenches who have encountered such generator backup systems. Come on, how many of you, besides Don, have connected the inverter to the gen-tran main panel (with no disconnection relay) without a problem? Anyone else had a bad experience, like Jeff? Thanks, -Kelly Kelly Keilwitz, P.E. Whidbey Sun & Wind, LLC Renewable Energy Systems NABCEP Certified PV Installer 987 Wanamaker Rd, Coupeville, WA 98239 PH & FAX 360-678-7131 [EMAIL PROTECTED] On 11/19/08 9:21 PM, "Jay Peltz" <[EMAIL PROTECTED]> wrote: > Hi Kelly > > I think what happens if the inverter backfeeds the genny, the > generator voltage will go up, if it goes up enough, it will go outside > the window of the inverter and the inverter will drop out, voltage > will them return to normal, inverter will reconnect and repeat. > > But I sure wouldn't want to fix the generator. A relay powered from > the grid will take care of the problem. > > jay > > peltz power _______________ > On 11/19/08 8:52 PM, "Drake Chamberlin" <[EMAIL PROTECTED]> wrote: > It is recommended to use a relay to disconnect the inverter when the > panel is being fed by the generator. _______________ On 11/19/08 7:28 PM, "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> wrote: >That is the way I see it. I have tested systems with gens and had no >issues. The Sunny Boy would not boot to a gen source. However, you can >understand what the official position must be. There exist gensets with >accuracy or it might just happen by chance. Low probability, but not >zero. > > Don Loweburg ___________________ On 11/19/08 9:42 PM, "Jeff Clearwater, Village Power Design" <[EMAIL PROTECTED]> wrote: > > We burnt up a gen set's voltage regulator on an off-grid system sunny > island/sunny boy system when we took the sunny island's off-line but > didn't shut off the sunny boy. So the SB backfed the genny and fried > the very expensive voltage regulator on a 30 KW system. SMA had us > install a relay to tell the SB to shut down as soon as the AC > reference from the SI was gone. Same situation as grid-tie really in > terms of your question. > > Jeff _______________________________________________ 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 _______________________________________________ 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
