Thanks, Chuckles159.
I just saw this phase drift from two non-identical frequencies you mentioned while dual-tracing two AC sources on an O'scope. At first I thought they would lock phase and freqeuency once the sync check breaker tripped if the phase and frequency were about 2% of each other...
Thanks STEVENAL, but that's the inverter I mentioned above. The OK4U was originally called Microsine 100, but they're no longer in manufacture and there's only a few floating around. In fact the site you mentioned states on their home page at
http://www.solarempowered.com that they are on back...
Thanks everyone for the follow up input. It's amazing how once you walk through the door of a bridge rectifier or transformer with DC how difficult it is to return to a simple parallel connection as with DC. I really appreciate the input.
I have worked quite a bit with Trace equipment on some...
stevenal:
I regret if I gave the impression that standards should not apply, rather I do firmly believe in uniform standards. It's just that I hear of many cases where on public systems leading technology experts are having to answer to the bureaucrats, the politicians vs. simply satisfying the...
Thanks for the input. This is a unique application that requires I bring the small sine wave inverter on line periodically vs. just solely powering dedicated load(s)with the inverter or having the inverter always on line, etc. It falls between the cracks of UPS systems, stand alone battery input...
I totally agree. I do believe there are issues with grid tied inverters just as there are issues with generators coming on line. It's just that when you look at the leading inverter MFRs and where you have in some cases several hundred 2500 watt inverters paralleled into a Main on a single site...
I'm in unfamiliar territory on this particular matter. I have a case involving a privately owned, off grid power system and we want to parallel two 120 Vac sources; the AC main (sine wave) and a small sine wave inverter. We only need 100 to 200 watts from this 120 Vac inverter. I've got control...
busbar:
Yes, thanks, I had gotten the Basler info after buzzp mentioned the sync check relay which was very helpful too. If it weren't for the over-scaled +/- List $1000 each for the auto-sync units or if the mini inverter I first mentioned was available in 120v/60Hz I'd be done. But now it's...
On a privately owned system there's less of a safety issue since (at least in this case) the operator(s) know and fully control the system, where in a public grid you have all kinds of potential issues. The modern grid tie or grid interactive inverters shut down in like 30ms if the line drops...
Follow up:
If you're in the U.S., this company sells inexpensive, reliable relay-based auto transfer switches for smaller 120/240 Vac applications like yours. They even have a 30 to 60 second delay so your generator warms up before the transfer occurs...
You do have to isolate your critical circuits if the generator can't power the whole house. If you don't isolate them into a sub-panel, even with a transfer switch, whether auto or manual you'll potentially have loads on in the rest of the house that you can't run simultaneously with a 4400 watt...
Thanks BUZZP:
I've checked further into sync check relays and may have found something I can work with. It may not be a home run or exactly as I need it, but I think it will get me to third base, and I think I can get it the rest of the way with a couple small, inexpensive peripheral items.
Thanks Guys.
Yes, Exeltech would be long shot. They know how to do it, but again, their whole product scale is for much larger applications, so like the other MFRs they don't offer it in a smaller scale and would have no desire to do it for just 50 units.
In the U.S., there was the one small...
Thanks, but that's actually why I'm here trying to see if anybody knows how to do it on a smaller scale. I can get a sine wave inverter that will grid tie, but they start on a scale of 2500 rated watts and cost $1500+ each because they also have internal battery chargers and auto-transfer...
Yes, thanks. I'm thinking I have to be able to sync-check voltage, phase angle and frequency, but here's where I get confused, like does the AC main then dictate to the small inverter in this process, so the circuit has to be able to force the smaller inverter into sync with the main or does it...
