When your voltage amounts are unstable (ie: power stays on, but the actual voltage stage varies quite a bit from the 220V standard), then I think that's the sort of situation exactly where an AVR is helpful. That UPS's output good quality is just not bottom with the barrel. Will https://google-map07394.bloggazza.com/32832347/getting-my-uninterruptible-power-supply-pdf-to-work