didn't someone tell me that telco equipment had 40vdc racks once?

[Brian Kelsay]

Unless those DC rack supplies are ten times more expensive to replace and
more likely to fail than a server power supply and harder to find.


On Dec 21, 2007 1:52 PM, Jonathan Hutchins <> wrote:

> The point of all this is that instead of every piece of equipment having
> it's own switching power supply, with fan, you supply the required
> voltages to the whole rack from a common pair of fail over power supplies.
> Each box then gets it's own +12,+5, and -5 (or whatever), and we have one
> less component per unit to fail.
>
> Converting the power once then distributing it really does beat
> distributing the AC and converting it at each unit, there are savings in
> equipment cost, efficiency, and cooling.
>
> Because of this, a 48 volt distribution system doesn't make as much sense,
> nor  does it offer as much advantage over a 120/240V AC distribution
> system.
>
>
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