Originally Posted by X96mnn
Not looking for the battery back up part but the voltage and serge protection.
An AC utility demonstrates a typical UPS output. First (leftmost) waveform is a UPS output when AC input connects directly to UPS output. Waveforms on right are a UPS output when in battery backup mode. View Tech Tip 3
UPS manufacturers quietly recommend not using a UPS on motorized appliances. That 'dirty' power can be problematic to motorized appliances. But is perfectly ideal for electronics. Electronics are more robust. So robust that even a 'dirtiest' UPS provides power that does not damage any electronics.
This 120 volt sine wave UPS outputs 200 volt square waves with spikes up to 270 volts. It is sufficient and safe for any electronics.
A typical UPS connects AC mains directly to an appliance when not in battery backup mode. It does not clean or regulate voltages. But a manufacturer makes subjective claims in advertising to imply such cleaning. They can lie all they want in subjective brochures. But not lie in specification numbers.
If a UPS does clean or regulate those voltages, then specification numbers defines it (ie %THD). 'Cleaning' numbers are forgotten for one reason. 'Cleaning' exists subjectively. That myth increases sales.
Same applies to surge protection. A hundreds joules surge is converted by electronics into rock stable, low voltage DC to safely power its semiconductors. How many joules does that UPS really claim to absorb or block? Near zero. So few that the surge is made irrelevant by what is already inside electronics. But just enough so that the numerically naive will call it 100% protection.
Tie a knot in a wire. Even that 'cleans' (filters) AC electricity. Then add numbers. It is near zero cleaning. Numbers expose a fallacy.