Ok... i pulled a 2500VA UPS apart... what is this?

[Any name you wish]

It looks just like an isolation transformer. This video even calls it a transformer:

However, it appears to be missing some wires.

 

[Smokin]

It's PFC look at the watts and VA difference. WOW L-C circuit COOL. 1 IGBT strange but COOL.

Alpha Technologies CFR 1500 Operator's Manual (Page 46 of 76) | ManualsLib

www.manualslib.com

 

[Maintenance guy]

That's what I think it is part of an LC smoothing circuit from AC to DC probably. I built a 100 volt 3 amp power supply for my needs and it uses an LC circuit for smoothing which is also large because the large inductances are needed for smoothing. it is much better then an RC circuit which waste power through heat.

 

[vk2emp]

I'm guessing it's a choke to help shape the pure sine wave output.

Highlly likely, it'll be wired as a low pass filter to remove harmonics and high frequency noise from the waveform. The parts need to be rated to take the full power of the ups - Assume the ups is rated to 3000VA peak power, the parts will probably be able to take 3500-4000VA before they begin to let out the magic smoke.

The same circuit is used in radio trainsmitters. If I look inside my Icom IC-7300 theres a board with a pile of chokes and caps, and with some smarts in the firmware it can select a suitable cap and choke (after sounding like an angry rattlesnake as it hunts for the correct combo) to match the radio to an antenna. Taking apart my Low Pass Filter (30mhz or below) it has a gigantic inductor (choke) and cap.

 

[robby]

I guess it is a MASSIVE inductor...
Only two wires on it.
Winding appears to be solid #6 varnished flat conductor.
Wood core, iron cage.
Weighs about 40Lbs...

Both of the Transformer looking Inductor and the Module you have show look like Filter Circuits to Eliminate Harmonics in the Generated AC when the unit is on battery power. There should be a large Capacitor in that same circuit. The module is most likely the control circuit for controlling PF.