Power regenerators X Power Conditioners

thats a mixed question as the THD is usually a result of interaction with a particular load-so it cant really be told unless you specify your phase leads/lags etc...
The IGBT units are the best at fitting the general specs. like 3rd order harmoinics which are common in audio stuff. but thats a vauge guess.
i would consider running my crown THD unit but its too valuble to me to start putting it on line level stuff. even though ive had it on my techrons 10ks but in a special enviroment.
you have to really measure your power phase in on idle and full load and calculate the shift necessary. I can come up with an awsome value at idle to advertise and impress you but it will be a trick..
if you run it on the battery it will be = to zero.

[ hemigreg ]buy a used commercial UPS for 800 and have better power quality than any "regen" unit cause thats what they are without the battery.

https://www.ebay.com/itm/APC-Smart-UPS-XL-3000VA-RM-5U-SUA3000XL-New-Batteries-1Yr-Wrnty-FreeShip/11...''

I presume you're using the filter provided by the UPS, is that correct?
If so, why not just buy a power filter?

That is, my understanding is that the UPS generates AC from DC if/when: (1) there's a loss of power (from the wall) (2) there's a battery in the unit. Otherwise, the UPS simply filters the AC coming from the wall and keeps the batteries charged.

So, no battery equals no DC, hence no generation of AC from the UPS.
Is that not correct?

Actually,
I just spoke with the technical support folks at APC and learned that their SRT line (e.g, SRT 3000 XLA) will convert AC to DC, and regenerate AC (pure sinewave) from DC even without a battery.