[RFI] RFI Digest, Vol 99, Issue 5

Charles Coldwell coldwell at gmail.com
Sun Apr 10 04:36:28 PDT 2011

On Apr 9, 2011, at 6:43 PM, Peter Laws wrote:

> On Sat, Apr 9, 2011 at 15:04, Allen Griffith <n5ag at verizon.net> wrote:
>> hello,
>> I just put 13 panels and inverters on line. I will gather info as time goes on.
>> I already have trouble with the system shutting down due to AC phase
>> problem....bummer.  This is going to be a heck of a ride I think.  This is only
>> the first full day of operation.  Kind of bumpy so far.
> I gather it's grid-tied (UL-listed inverters stop passing AC when the
> grid power drops ... or is crappy).

Indeed, this the "anti-islanding" requirement of UL-1741 for inverters.  The idea is that the power company may have turned off the power intentionally to allow work on the line, so if your home generation system is still energizing the wires you could electrocute a lineman.

From an engineering standpoint, it also makes sense because the inverter power should be phase locked to the mains; when the mains disappears there's no reference oscillator to lock to!

I'm curious to know, what inverter are you using N5AG?

73 de W1CMC

Charles M. Coldwell, W1CMC
"Turn on, log in, tune out"
Belmont, Massachusetts, New England (FN42jj)

GPG ID:  852E052F
GPG FPR: 77E5 2B51 4907 F08A 7E92  DE80 AFA9 9A8F 852E 052F

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