Cisco 7000 Series Hardware Installation And Maintenance Manual page 22

Physical Description
On the AC-input and DC-input power supplies, the green DC OK LED indicates the status of the
power supply and internal DC voltages. The DC OK LED stays on when all of the following
conditions are met:
•
•
•
If the AC or DC source power or any of the internal DC voltages exceeds allowable tolerances, the
DC OK LED goes off and the system environmental monitor messages indicate the line that is out
of tolerance. Because the RP (which uses +5, +12, –12 VDC), and the fan tray (which uses
+24 VDC) are both required for operation, the system will probably shut down if any internal
voltages reach an out-of-tolerance state.
Inside the AC-input or DC-input power supply, two small fans draw cooling air through the power
supply interior. The air flows in one side of the supply and out the other side, following the same
direction as the chassis cooling air. (See Figure 1-6.)
In addition to the environmental monitoring performed by the system software, the power supply
monitors its own temperature and internal voltages. If the supply detects an overvoltage, or
overtemperature condition, it shuts down to avoid damage to the power supply or other system
components. For a description of power-supply shutdown conditions and thresholds, refer to the
section "Environmental Monitoring and Reporting Functions" in this chapter.
The AC-input and DC-input power supplies are available as spares for immediate onsite replacement
in case the existing power supply fails. The chapter "Maintenance" provides power supply
replacement instructions. In addition, detailed, up-to-date instructions are included with all spares
when they are shipped from the factory.
Figure 1-6
Top view of router
Chassis
airflow
Power supply
airflow
1-8 Cisco 7010 Hardware Installation and Maintenance
AC power supply is on and is receiving 100-240 VAC, 50-60 Hz source power or the DC power
supply is on and the system is receiving –48 VDC in North America (or –60V in Europe).
Power supply is providing the +5, +12, –12, and +24 VDC to internal components.
All internal DC voltages are within tolerance.
Internal Airflow, Top-Down View
Power supply fans
Interface processor end
Service (noninterface processor) end
Chassis fans
Fan tray
Power supply
airflow
Chassis
airflow