[c-nsp] 6509 DC power question-

[Pete Templin]

On 2/16/11 3:52 PM, Luke Pack wrote:
> Greetings everyone,
>
> We have a 6509 switch with sup2 engines.  For upgrade capability, we
> have the 2500W DC power supplies in this.  I have an A/C unit with the
> same engines/cards at a separate location, therefore I expect this
> unit to require the same amount of power.  Here is the "show power"
> from the A/C unit in production:
>
> #########show power
> system power redundancy mode = redundant
> system power total =     1153.32 Watts (27.46 Amps @ 42V)
> system power used =      1011.78 Watts (24.09 Amps @ 42V)
> system power available =  141.54 Watts ( 3.37 Amps @ 42V)
>
> At the location, it looks like we are only going to get 50A dropped to
> our rack.  This drop will be ONLY for the 6509.  In the documentation,
> they say 70A input is needed for these 2500W PSUs
>
> My question is this:
> Given that my power requirements on the unit are below even 1300W,
> will the 2500W power supply run/work on the 50A provided just with
> lower output or is the 70A absolutely necessary?  If 50A will not work
> I will simply order 1300W DC Power supplies and save the 2500W ones
> until such time as we upgrade to sup720s etc.

 From the output above, your reference AC-powered unit is running on 
120V input power, causing the supplies to only offer 1153W to the 
system.  Give them high-range power (170-268V I believe, meaning 208V or 
240V in reality) and you'll have more power available using the same 
supplies.

In your upcoming DC scenario, you'll draw 25-30A if running on one 
supply, 13-15A/supply if running on two.

You'll be fine on 50A fuses.

pt