From: already5chosen@yahoo.com   
      
   On Fri, 26 Sep 2025 14:28:02 GMT   
   scott@slp53.sl.home (Scott Lurndal) wrote:   
      
   > BGB  writes:   
   > >On 9/25/2025 9:03 PM, Scott Lurndal wrote:   
   > >> MitchAlsup  writes:   
   > >>>   
   > >   
   > >>   
   > >> Consider that there are losses converting from the   
   > >> primary (e.g. 22kv) to 480v (2%), and additional losses   
   > >> converting to 208v (3%) to the UPS.  That's before any   
   > >> rectification losses (6% to 12%).  With various optimizations,   
   > >> they reduced total losses to 7.5%, including rectification   
   > >> and transformation from the primary voltage.   
   > >>   
   > >   
   > >Hmm...   
   > >   
   > >Brings up a thought: 960VDC is a semi-common voltage in industrial   
   > >applications IIRC.   
   >   
   > > What if, opposed to each computer using its own power-supply (from   
   > > 120 or 240 VAC), it uses a buck converter, say, 960VDC -> 12VDC.   
   >   
   >   
   > In those datacenters, the UPS distributes 48VDC to the rack components   
   > (computers, network switches, storage devices, etc).   
      
   I looked at PSUs offered by Dell for their rack servers. There are four   
   options for the inputs, although not every server model has all four.   
   The options are:   
   - 100-240 VAC.   
   - 200-240 VAC   
   - -48 VDC   
   - 240-400 VDC   
      
   I don't know in which countries and in which branch of IT they prefer   
   the fourth option, but knowing Dell of late (as opposed to Dell of up to   
   ~2008), they would not offer the option unless demand was quite   
   significant.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)