There not any high inductive load in the house to note.
That probably helps, but even with purely resistive loads the issue I mentioned still exists. (more later).
The mechanical ATS I was using uses 2 60a rated disconnects motor switched of course. Somewhere I have a contactor rated for 80a (our service is only 60a) but I lack the circuitry to switch it like an ATS . I had always wired the ATS as the inverter being grid, lose the inverter, switch to the grid.
I suppose a simple logic circuit would do the trick for a mechanical ATS. Maybe simply energizing a 2 pole contactor from the 220v out as the inverter comes online
When I was on-grid (I had 3-phase power too), I had two, mechanically interlocked 3-phase contactors. It was physically impossible for both to have their contacts engaged at the same time.
The grid 3-phase fed 3-phase to the big loads (mainly a big HVAC). When running on genset (which was single-phase), it would drop the grid contactor, and as soon as practical afterwards (mechanical interlock) would pull in the genset contactor. It was wired so the single phase fed all 3 phases together. The advantage with this was the aircon used phase-to-phase for its control relays, so it simply couldn't operate in this mode, but everything else did
So Ross, your saying it’s possible that since there was no delay during switching that the triacs were held open without time for a close cycle then grid and inverter were connected until poof?
Hypothetically, lets say you have grid (A) and inverter (B), both waveforms exactly 50Hz, pure sine, identical voltage, free-running inverter with no phase lock.
Using src/triac as switches with simple gate triggering, lets assume for the point of argument that you're running on inverter (input B) and the triac is being (re)triggered constantly. Then, the grid is restored. You try to change from inverter to grid after waiting a few seconds to be sure it's back and stable.
Lets also assume that at the time you go to switch, the grid is 90 (electrical) degrees ahead of the inverter. You turn off the trigger to input-B and immediately trigger input-A with no delay. The B input triac will continue conducting (because it is still passing current), but now triac A will turn on (at the next zero-crossing, which is only 90 degrees away). Triac A will also trigger and you have inverter and mains connected together, but 90 degrees out of phase. (There are worse scenarios - 270 degrees is a much bigger bang)
Spent all days Saturday in bed with body aches. My daughter came back from her Moderno second shot and got fever and body aches and mysteriously I do too the next day. I had the Johnson & Johnson last April with same effect, miserable all night.
Yuck. It's taken me months, and eventually friends in high places to pull some strings, but my wife and I both got our second pfizer shots (wife on tuesday, I got mine yesterday). Been too busy to notice any side effects whatsoever beyond a slightly sore arm at the injection site.