[Elecraft] OT - Computer PS/UPS Question

[kc4kgu@ENTERZONE.NET]

On Sun, 2 Jun 2002, Larry East wrote:

> Hi -
> 
> I recently acquired a UPS with a dead battery (standard 7.2AH 12V SLA) for 
> a couple of bucks at a "junk store". There is the following notice on the 
> bottom of the unit: "When operating from battery power, output is 120V 60Hz 
> rectangular wave form. User should take care to determine prior to use 
> wether this device is suitable ..." blah blah. I assume that this thing is 
> intended for use with computers, but before I spring for a new battery, I'd 
> like some input on whether or not desk-top computer power supplies are 
> picky about the input AC wave form. I'm looking for actual experience, not 
> "intelligent guesses"... :-)
> 
> Tnx & 73,
> Larry
> 
> PS: Yeah, I know -- if I spring for a new battery and the UPS blows my 
> computer supply, I could still use the battery to power my K2 ... but I'd 
> rather not take an "experimental" approach!

Most computer supplies that I have seen (and we run a datacenter with @
1000 servers in it) are more picky about the frequency and voltage than
about the waveform.  I haven't taken the scope to any of the APC UPS's we
have but I would venture to guess that they are going to be square or
sawtooth.  The only UPS we have that I *know* produces nice sinewave is a
$60,000 Liebert UPS that is designed to run its own 100A panel.  It takes
208/240V 100A input and feeds a standard 100A single-phase panel on its
output providing both 120V and 240V @60Hz.

The educated guess is that you're just fine running your home computer on
the UPS you purchased.

73 de John - KC4KGU
K2/100 #2490