two Trace SW4048's in parallel [RE-wrenches]

[Joe Schwartz, Home Power]

<x-flowed>>2.  You may need separate, isolated neutral busses for each inverter in the
>panel. May not. I've had some strange feedback into the Trace SW's from
>common neutrals, and think this may cause a problem. (Something like the
>inverter #2 thinking that it is getting its supply fed back into it's
>input.)
>
>Anyone else have an opinion on this?

We run four inverters up at Home Power. Neutral is common among them 
via the neutral/ground bond. I was concerned that this would be 
problematic. The inverter manufacturers didn't seem to like the idea 
either but couldn't come up with any technical reason why this 
configuration wouldn't work. Neither could anyone else I talked with. 
We went ahead with the common neutral configuration and everything 
works just fine.

To isolate the inverters from one another separate neutral AND 
equipment ground systems would be necessary (raceways, conduit if 
metallic, etc...) Besides being a  headache, this leads to other 
problems like varied potential to ground in the individual systems.

Joe Schwartz

>
>Jeff
>
>Jeffery D. Wolfe, P.E.
>Global Resource Options, LLP
>A Woman-Owned Vermont Limited Liability Partnership
>4 Kibling Hill Road
>P.O. Box 51
>Strafford, VT 05072
>802/765-4632
>802/765-9983 (Fax)
>global at sover.net
>www.globalresourceoptions.com
>
>
>----------
>From: 	David Palumbo, Independent Power & Light[SMTP:ipl at sover.net]
>Reply To: 	RE-wrenches at topica.com
>Sent: 	Saturday, August 19, 2000 3:52 PM
>To: 	RE-wrenches at topica. com
>Subject: 	two Trace SW4048's in parallel [RE-wrenches]
>
>Wrenches,
>
>We are adding a second SW4048 onto a system for two reasons.
>	1) To increase the speed of battery charging (system has a 
>large 120/240
>Kohler genset).
>
>       2) To provide backup inverter power in case one of the SW4048's
>should
>fail.
>
>This is a 120 volt system only so we will not be series stacking the two
>SW4048's. The client
>also does not need any more power on one circuit than one SW will supply.
>
>Our idea is to keep the SW4048's independent of each other and simply wire
>each inverters
>output hot wire to a different leg in the AC load center. We have
>successfully done this with
>two Exeltech 1100's and I don't see why this should not work with SW4048's.
>It is relatively
>easy to balance the home's various circuits so that all of the big loads
>will not be fed from
>one inverter. For instance we will make sure that the water pump and
>washing
>machine are fed from
>different inverters.
>
>By doing it this way we will save our client the $ 345 for the Trace
>SWI/PAR
>paralleling kit.
>Plus the extra labor to install, and the added system complexity.
>
>We wanted to float this idea out to the list in case we are missing
>something.
>
>David Palumbo
>IP&L
>
>- - - - - - -
>To send a message:
>  RE-wrenches at topica.com
>
>The archive of previous messages:
>  http://www.topica.com/lists/RE-wrenches/
>
>To unsubscribe send a message to:
>  RE-wrenches-unsubscribe at topica.com
>
>To check out the other RE-Wrench participants:
>  www.mrsharkey.com/wrenches/index.html
>
>Hosted by Home Power magazine:
>  www.homepower.com
>
>For info contact list moderator by email:
>  michael.welch at homepower.com
>___________________________________________________________
>T O P I C A  The Email You Want. http://www.topica.com/t/16
>Newsletters, Tips and Discussions on Your Favorite Topics
>
>- - - - - - -
>To send a message:
>  RE-wrenches at topica.com
>
>The archive of previous messages:
>  http://www.topica.com/lists/RE-wrenches/
>
>To unsubscribe send a message to:
>  RE-wrenches-unsubscribe at topica.com
>
>To check out the other RE-Wrench participants:
>  www.mrsharkey.com/wrenches/index.html
>
>Hosted by Home Power magazine:
>  www.homepower.com
>
>For info contact list moderator by email:
>  michael.welch at homepower.com
>___________________________________________________________
>T O P I C A  The Email You Want. http://www.topica.com/t/16
>Newsletters, Tips and Discussions on Your Favorite Topics


-------------

Joe Schwartz
Home Power Magazine
PO Box 520, Ashland, OR 97520  USA
email:joe.schwartz at homepower.com
Web: http://www.homepower.com

- - - - - - -
To send a message:
 RE-wrenches at topica.com

The archive of previous messages: 
 http://www.topica.com/lists/RE-wrenches/

To unsubscribe send a message to: 
 RE-wrenches-unsubscribe at topica.com

To check out the other RE-Wrench participants:
 www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine: 
 www.homepower.com

For info contact list moderator by email:
 michael.welch at homepower.com
___________________________________________________________
T O P I C A  The Email You Want. http://www.topica.com/t/16
Newsletters, Tips and Discussions on Your Favorite Topics
</x-flowed>