any one can help me?about the power supply of cisco 2821-DC

[wei jin]

hi all:

    i got one cisco 2821-DC  ,i have some doubts about the product datasheet:

   DC Input Voltage：24-60 VDC(autoranging positive or negative)

   DC Input Current：

    ● 12A (24V)
    ● 5A (60V)
    ● Startup current 50A<10 ms

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1、it can be used in -48V direct current supply?(what's the meaning for autoranging positive or negative)? if yes,plz tell me how to do it

2、the Startup current is 50A? i think it 's too larger than my capacity of air switch(32A all)

thx

[wei jin]

up....

[wei jin]

any one here?

[dixho]

Search internal database. Find out that 2821-DC can operate between 24V to 60V; however, the amount of current draw from your DC source depends on the modules installed on the router. Using formular power = voltage x current. If you install too many modules on the router, you may burn your power source.

Please be aware of that the effeciency of the DC power supplies is lower than AC power supplies. Make sure that your DC source can handle the load.

I am researching on the autoranging question.

[wei jin]

thx a lot.

Looking forward to your answer.

[suresh_mds]

Hi the DC input current of 2821 is 12A (24V), 5A(60V) startup current 50A<10ms. Power dissipation of DC is 300W (1024 BTU/hr). RPS recommended is RPS-675.

Hope it helps.

Thanks

[wei jin]

thx

But that is not what I want.

My power system is DC(-48v) , so i just want to know whether the 2821-dc can working well or not

because according to the datasheet , the voltage range of the 2821-dc is 24 to 60 V

so is that mean it just can work with +48v power system ?

and dixho is still not give me any explain about the "autoranging positive or negative"

....

i really need more information

thx all

[wei jin]

up..

[dixho]

Hi,

I suggest that you go to the following URL:

http://www.cisco.com/en/US/docs/routers/access/2800/hardware/installation/guide/01_hw.html#wp1093284

Table 10 shows that "24 to 60 VDC, positive or negative". Thus, -48V should work. The autorange means that the router can detect the voltage of the power source.

Do you have other questions?

[wei jin]

hi dixho

" The autorange means that the router can detect the voltage of the power source."

I don't quite follow you. the router can detect the voltage . is that mean both +48v and -48v power source can supply to the router(and i also want to know is there any difference for wiring pattern?)

Thank you very much for answering my questions DIXHO

I'll be waiting for your reply

[wei jin]

up