[RE-wrenches] Outback AC coupling Sunpower?

[Drake]

I did AC  couple a Magnum inverter to an existing Sunpower 
system.  It works. The Magnum features frequency shift control, but 
recommends the use of a protective relay also.

At 04:59 PM 7/30/2013, you wrote:
>Hi All;
>
>I know AC coupled systems have been covered before, but I have a new 
>issue:  positive grounding.  A customer with an existing 8kw 
>Sunpower system wants to add backup.   He was put off by the high 
>cost the Sunny Island, so I was steering him towards a single 
>Outback VFX coupled to just one of his 3 inverters.  The issue is 
>how will the VFX work with positive grounded inverters.  I'm 
>assuming that since the two inverters will only be connected by AC, 
>that the positive vs negative grounding of their separate DC systems 
>will not matter.  Any experience with this particular scenario: 
>Sunpower system AC coupled to an Outback?
>Also, would I even need a GVFX, since the inverter would only be 
>used during outages  (which might allow a generator to be used later 
>as well)  A VFX should still AC couple to the GT inverter during an 
>outage, right?
>
>Thanks as always,
>
>--
>R.Ray Walters
>CTO, Solarray, Inc
>Nabcep Certified PV Installer,
>Licensed Master Electrician
>Solar Design Engineer
>303 505-8760
>
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