westom

All electronics work perfectly find even when incandescent bulbs dim to less than 50% intensity. I who design electronics must meet that and other standards. We routinely reduce voltages even lower to learn at what point it simply powers off.

Electronics must work perfectly normal at voltages that would be harmful to the furnace, dish washer, and refrigerator. If that voltage goes lower, electronics simply turns off. No damage must even happen. But that low voltage can be harmful to any motorized appliance.

Meanwhile a UPS connects the sewing machine directly to AC mains when not in battery backup mode. Where is the protection? Some of the 'dirtiest' power seen by any appliance is the UPS in battery backup mode. So 'dirty' as to be harmful to small electric motors and power strip protectors. And perfectly ideal for any electronic appliance.

If a UPS does what so many have claimed, then unique manufacturer specifications can be provided. Good luck finding those numbers. Meanwhile, electronics are so robust that 'dirtiest' power from a UPS (in battery backup mode) is not harmful. A UPS has only one function. To provide temporary (and dirtiest) power during a blackout.

So how often are your lights dimming to 50% intensity? Rarely? Never? They why spend £50 on a UPS? Its only purpose - temporary and dirty power during a blackout.

The original post asked for surge protection. No UPS claims that surge protection. But again, because this defines which solutions actually work. A protector is only as effective as its earth ground. Effective protectors connect 'less than 3 meters' to that single point ground. Protection is always about where energy dissipates. Products with obscene profit margins hope you never learn that important fact.