[geeks] Memo to self: try not to destroy UPSs

[geeks at sunhelp.org]

auction.apcc.com

On Mon, 18 Jun 2001, Kris Kirby wrote:

> 
> Memo to self: Try not to destroy UPSs. It's really not a good idea to
> "MacGyver" UPSs in the first place, but to use a fuse that is underrated
> is almost as hazardous as to use one too large.
> 
> Background
> ---------
> 
> I took an older APC Smart-UPS 600 and ran #8 wires out the back to an
> external battery pack which, for the time being, are cells of the exact
> size that would normally be in the UPS. The #8 wires have an inline
> automotive-style fuse holder holding a 20A fuse. Well, the fuse almost
> melted into the holder, leaving a large hole in the bottom of the fuse
> itself.
> 
> Fscking cool; that 600 held up about ~500W of load (at *least*). I smelled
> the [plastic] burning and thought "SH*T! Lost another UPS!" UPS was fine;
> the fuse had it.  24V x 20A = 480W.. oh yeah. :)
> 
> I'll get the pictures up soon; I just racked most of my machines
> tonight. :-)
> 
> Power diagram (until failure ;-)
> 
> Utility ---> Smart-UPS 600 (Sine) ---> Belkin 525VA -------> Machine
>                                    |                 \-----> Machine
>                                    |-> Belkin 525VA -------> Machine
>                                    |-> Belkin 525VA -------> Machine
>                                    \-> APC Backups 300 ----> Ethernet
>                                                        |     Bridge
>                                                        \---> 100Mb/s
>                                                              Switch
> 
> The Belkins and APC are square-wave. The Belkins also don't like to switch
> under full load; they'd rather dump the load. :-(
> 
> -----
> Kris Kirby, KE4AHR          | TGIFreeBSD... 'Nuff said.
> <kris at nospam.catonic.net>   |    
> -------------------------------------------------------
> "Fate, it seems, is not without a sense of irony."
> 
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