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RE: BBN (GTE) Suffers another major power problem.

  • From: Jonah Yokubaitis
  • Date: Sat Aug 09 05:11:38 1997

On Fri, 8 Aug 1997, Rodney Joffe wrote:

|> Incorrect. Stop using AC equipment in your pops. Use DC equipment and
|> get a _good_ DC Powerplant. Every carrier Class4/5 switchroom usually
|> has 10-20,0000 AMP/hours of standby power.  1 DSC or Nortel switch
|> sucks _quite_ a bit more power than even the largest of superpops.
|> Every carrier has _at least_ 4hours of battery plant (most have 8-12).
|> Relying on generators is a _bad_ idea.
|> Its not hard to have 4-12hours of standby battery plant.
|> Lucent/Lorain/Peco2 all make rather nice rectifiers, and
|> C&D/Lucent/GDB all make some nice vented batteries.  By going DC you
|> also don't get hit with the inefficiencies of AC --> DC --> AC --> DC.
|> You can bet that MCI/Sprint don't have a piece of AC equipment in
|> their facilities and most likely are laughing their asses off right
|> now.
|Not quite as simple Jonah.... CO equipment is designed for 48v for many
|reasons. It's also designed to deal with concrete floors, inefficient
|HVAC, dust, etc.
|Unfortunately, a modern megapop consists of a lot of interesting
|equipment that doesn't come in 48v DC versions. Alpha 8400s, Large SGIs,
|and server like things (yeah, I know, there are companies who make
|retrofit kits for some of them, but they're not standard).

Use invertors off your -48VDC plant for your AC equipment. 


AC feed from electric co --> rectifier --> DC batteries --> inverters

I have yet to see an AC UPS with a longer runtime than 2hours (100KW+)
with full battery options installed. Exide/Liebert make excellent UPS
systems, but they are _not_ meant for extended runtime. Instead they
are meant for a graceful shutdown of all systems when extended power
outages occur.