Incorrect WTom, most UPS's also protect from Surges or Sags in the Power
to the device they are protecting. Many UPS devices have "automatic
voltage regulation" as well as quality SURGE suppression.
Computer grade UPSes connect an appliance directly to AC mains when
not in battery backup mode. 'Cleanest' power comes directly from AC
mains. In battery backup mode, this 120 volts UPS outputs two 200
volt square waves with a spike of up to 270 volts between those square
waves. 'Dirty' electricity is irrelevant because computers are so
robust. Power so 'dirty' as to even harm some small electric motors.
APC says same as posted on 10 Dec 2008 in "UPS or no UPS" at:
http://tinyurl.com/6zn9sr
Leythos calls that 'automatic voltage regulation'? Well, yes. When
120 volt AC mains drop something below 87%, then it switches to
batteries and outputs square waves.
Arthur Buse also describes that UPS output in "Filthy Dirty Power..
maybe" on 2 Nov 2008 at:
http://tinyurl.com/6nerja
A cheap UPS, when the mains are supplying the power, just
connects the computer to the mains power using a relay. ...
Mains electricity is a pure sine wave, a gentle curve of a single
frequency. The inverter puts out a ghastly square wave type
thing which contains just about any frequency you can imagine.
Arthur Buse simply confirms those numbers. When the mains are
powered, a UPS connects power through a relay - a direct connection.
When mains fail, output from an inverter is so nasty as to be harmful
to some appliances - but irrelevant to robust protection in all
computers.
Leythos is invited to post those manufacturer spec numbers that
claim protection from each type of surge. He will not because he
cannot.
Let's see. Another UPS spec says 200 joules of protection.
Destructive surges are typically tens or hundreds of thousands of
joules. So 200 joules will absorb a 100,000 joule surge without
damage? Leythos is correct. It does claim a tiny surge protector
component. What Leythos cannot claim is useful or effective
protection. It claims a near zero protector component. Only enough
joules so that Leythos will _believe_ it has surge protection - and
then promote the myth.
From numbers, that UPS has 'virutally' no surge protection. No
wonder it will not list protection for each type of surge in numeric
specs. Some plug-in UPSes discuss filtering because of near zero
protection.
Serious UPSes (ie building wide UPSes) do provide surge protection.
Plug-in UPSes only provide protection in the myths that claim that
protection.
That UPS does not 'clean' electricity. It neither provides nor
claims to provide effecetive surge protection. Its inverter output
(in battery backup mode) is so 'dirty' as to be harmful to power strip
protectors - but not to computers.