AK6DN said:
Ok, but I still think you wasted your money on those devices.

They are AC/DC switching power supplies that are feeding a high power oscillator (ie, 120V/1000W at 60Hz).
Then you feed that AC to a second rank of AC/DC switching power supplies.
All you have done is created inefficiency (wasted power since no conversion is 100% efficient) in doing the AC/DC/AC conversion unnecessarily.

The switcher in your UPS is really no different than the switcher in your PC, just a different output setpoint (ie, 24VDC or 48VDC or whatever) vs 12V/5V/3.3V/1.XV outputs in your PC.
AC sinewave power is really only critical if you are using a transformer in the power path; and virtually no switchers do that any more.

What you are doing is not bad, it is just more expensive and basically unnecessary.
I used an Oscilloscope to test the output, as I need clean power without battery and with.
My cost is way less than you think, being in the IT business.