Chinese "Pure" sine wave AIO inverter AC quality.

[timselectric]

You haven't said so I guess you wouldn't recommend option no 1 (AIO powered by the grid, inverter on and powering one phase). That was my conclusion too.

That's why I'm talking about transfer times etc.

If you can see a problem with the same connection, but with option 2 (inverter bypass on the AIO) please elaborate.

I see a problem with it all.
Will the 3-phase loads work in full bypass mode, yes.
But, I don't know how many times the 3-phase equipment will protect itself, before failing.
It would be better to separate the loads that you want on backup.

 

[Luk88]

I see a problem with it all.
Will the 3-phase loads work in full bypass mode, yes.
But, I don't know how many times the 3-phase equipment will protect itself, before failing.
It would be better to separate the loads that you want on backup.

Thanks for claryfying. Yes, that's the long term plan. Weather permitting (as long as I can dig trenches on a weekend) I may even start with a proper system from the beginning.

 

[Luk88]

BTW, there is no option to have AC inverter on delivering from a battery and charge from AC at the same time for the SMH-ii-Xk range of "AIOs".

So that is not an option.

So other than the calculation I made, has anyone got any experience of frequent transfers on IT equipment?

Edit: Look what I found:
This is a standard which all PC supplies today have to adhere to.

---copied from a quora answer:
In Desktop Platform Form Factors Power Supply - Design Guide (a.k.a. The "ATX" spec) by Intel, page 20 and 21, the required hold-up time after a power interruption is specified.

3.2.9 Voltage Hold-Up Time - Required. The power supply should maintain output regulations per Table 3-2 despite a loss of input power at the low-end nominal range- 115 VAC / 47 Hz or 230 VAC / 47 Hz – at maximum continuous output load as applicable for a minimum of 17ms (T5+T6).
Parameter:

• T5 - AC loss to PWR_OK hold-up time: > 16 ms
• T6 - PWR_OK inactive to DC loss delay: > 1 ms

So, what does it mean? It means in theory, as long as the transfer time truly is under 17ms (10ms claimed for the AIO in UPS mode) it should be perfectly fine to engage the transfer all day long.

How is this relevant to my earlier calculation of HV capacitance on a high quality ATX PSU? Well, I have to assume the capacitance on the low voltage side is such that it "bridges the gap" so to speak up till these 17ms at full power.

So it should be perfectly possible to not have additional UPSes.

 

[timselectric]

BTW, there is no option to have AC inverter on delivering from a battery and charge from AC at the same time for the SMH-ii-Xk range of "AIOs".

So that is not an option.

All off grid AIO's are this way.
AC charging (input) and inverting (output), share some of the same circuitry.
So, they can only do one or the other, at any given time.

So it should be perfectly possible to not have additional UPSes.

Correct, in most cases.
We don't hear much about members having issues with transfer times.
Just every once in a while. I believe that the problem usually ends up being attributed to something else.