Modular Configuration Dc Power - Cisco SRS Series Installation Manual

Installing and Removing Power Components
Sometimes, the source DC cable leads might have a positive (+) or a negative (–) label, but you must verify
the polarity by measuring the voltage between the DC cable leads. When making the measurement, the positive
(+) lead and the negative (–) lead must always match the (+) and (–) labels on the power shelf.
Caution The DC input PEM contains circuitry to trip the breaker on the PEM if it detects a reverse polarity condition.
When installing DC power cables, make sure that the polarity of the DC input wiring is correct.
This figure shows the cable wiring for the fixed configuration power shelf.
Figure 14: DC Power Shelf Cable Wiring for Fixed Configuration Power Shelf
The table lists the fixed configuration DC input current and voltage specifications.
Table 2: DC Input Current and Voltage Information
Nominal input voltage
Input line current
Inrush current
Each wiring block on the fixed configuration power shelf contains two sets of terminals, one positive and one
negative, and is covered by a plastic block cover that snaps onto the power shelf and is secured by a screw to
a torque value of 4 to 5 in.-lb (0.46 to 0.58 N-m). You must remove the block cover or rotate it out of the way
before you work with the cables. The block covers are slotted in such a way that the cables can exit only one
end. For the cables to point in a different direction, remove the block cover, rotate it, and snap it back on.

Modular Configuration DC Power

The LCC modular configuration DC power system can provide up to 16,800 watts to power the chassis.
However, by default, the power capability of a system when shipped, with six DC PMs per power shelf, is
12,600 watts.
Note Depending on the hardware deployed at your site, your system may not consume the maximum power supplied
by the power system.
–48 VDC North America–60 VDC European Community(range: –42 VDC to –75
VDC)
50 A maximum at –48 VDC40 A maximum at –60 VDC
168 A peak at –75 VDC(maximum for 1 ms)
Cisco CRS Routers 16-Slot Line Card Chassis Installation Guide
Modular Configuration DC Power
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