Path: utzoo!attcan!uunet!usaos!wsrcc!wolfgang
From: wolfgang@wsrcc (Wolfgang S. Rupprecht)
Newsgroups: sci.electronics
Subject: Re: UPS's, printers & fried equipment
Keywords: references
Message-ID: <1990Sep27.144136.6154@wsrcc>
Date: 27 Sep 90 14:41:36 GMT
References: <1990Sep26.013510.23949@mthvax.cs.miami.edu>
Distribution: na
Organization: Wolfgang S Rupprecht Computer Consulting, Washington DC.
Lines: 23

wb8foz@mthvax.cs.miami.edu (David Lesher) writes:
>My esteemed employer is planning on adding a bunch of 286 machines
>to an existing UPS system. The problem is, that because of the
>limited capacity of the UPS, they want to run ONLY the PC's off
>of it, and will run the laser printers off of the unregulated,
>un-isolated ground, unprotected power.

I'm sure the UPS manufacturer would be pleased to cite papers or 
perhaps whip one up for you.  

I have pondered the same thing here and am toying with the idea of
running everything through the UPS, but have a cut-out relay for the
fluff when the power fails.  This way one gets the filtering from the
UPS and but doesn't melt down the inverter, or run down the UPS
battery by running laser printers and other power hogs.  One also
eliminates you problem of large ground-loops for the data connections.
You probably still have to play it close on the UPS rating though.

-wolfgang

-- 
Wolfgang Rupprecht    uunet!{nancy,usaos,media!ka3ovk}!wsrcc!wolfgang
Snail Mail Address:   Box 6524, Alexandria, VA 22306-0524