Cisco CRS-1 - Manual (Page 31)

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Cisco CRS Carrier Routing System 8-Slot Line Card Chassis Site Planning Guide
OL-5802-09
Chapter 2 Power and Cooling
AC Power Systems
Figure 2-7 shows the DC input power cables connected to the modular configuration DC power shelf
terminal studs.
Figure 2-7 Modular Configuration DC Power Shelf Power Cable Connections
Note In the modular configuration DC power system, the power wire connectors have a torque value of 20
in-lb (2.26 N-m).
Note An earth ground cable is not required for the modular configuration DC power shelf.
AC Power Systems
The Cisco CRS 8-slot line card chassis can be configured with either a fixed or modular configuration
AC-input power subsystem. The chassis power system provides the necessary power for chassis
components. Site power requirements differ, depending on the source voltage used.
Each AC powered chassis contains two fixed configuration AC PDUs or two modular configuration AC
power shelves for 2N redundancy. A fixed configuration AC PDU connects to an AC rectifier, while a
modular configuration AC power shelf can contain up to three AC PMs.
Fixed Configuration AC Power Requirements
A fixed configuration AC-powered LCC contains two AC power distribution units (PDUs) and two AC
rectifier modules. Each AC PDU is connected to an input AC power source and holds a single 7500-watt
AC rectifier. Input AC power enters the PDU and is passed to the rectifier. Here, the input AC power is
converted into the 54.5 VDC used to power components in the chassis. Each AC rectifier is field
replaceable and has its own circuit breaker.
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