difference between inverter and ups
Hi
UPS usually hires inverter stage inside, to convert DC supply (e.g. batteries) into AC power connected to the load. However, an UPS does not have to consist only inverter. Some UPS modules (e.g. on-line versions) should have rectifiers to charge batteries from outlet power. this is know as double-conversion:
Outlet --> Battery--> AC power to Load
I hope it helps little bit. If there is unclear points, let me know.
Cheers