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Catalyst 4500 E-Series Switches Installation Guide
OL-13972-02
Appendix A Power Supply Specifications
Environmental Monitoring Feature
Environmental Monitoring Feature
With the environmental monitoring and reporting feature, you can keep your system running by
resolving adverse environmental conditions before a loss of operation.
The power supply monitors its own internal temperature and voltages. In the event of excessive internal
temperature, the power supply shuts down to prevent damage. When the power supply returns to a safe
operating temperature, it restarts. If the power supply output voltage is not within the specified range,
the LED labeled OUTPUT FAIL will light. An instance of substantial output overvoltage can shut down
the power supply.
An instance of substantial input overvoltage (greater than –75 VDC continuous) can damage the power
supply input circuitry and can cause it to shut down permanently.
For a 1400 W DC power supply, the main power switch has an input range of –40.5 to –72 VDC, while
the –48 V PoE operates over a range of –40.5 to –56 VDC. The PoE either fails to start or shuts down if
exposed to greater than –56 VDC input. PoE recovers after you recycle input power within the proper
voltage range. If the PoE shuts down due to input overvoltage (greater than –56 VDC), the main
converter section does not shut down.
The supervisor engine monitors the status of each power supply and provides a status report through the
switch software. For more details on how the supervisor engine monitors the power supplies, see the
“Environmental Monitoring and Power Management” chapter of the
Catalyst 4500 Series Switch Cisco
IOS Software Configuration Guide
.
Power Redundancy
All Catalyst 4500 E-switches offer 1+1 power redundancy, so that in the event of a power interruption
the switch can still operate using power from another circuit. The power supplies can also run in a
combined mode so that chassis can have power from both supplies at once. Use the
power
redundancy-mode
command to configure combined mode. Redundant mode is the default.
Catalyst 4500 E-switches support power supply redundancy only between power supplies of equal
wattage and type. A mix of power supplies is not supported. The second power supply recognized is
placed into errdisable mode.
A more detailed discussion of power redundancy is in the “Environmental Monitoring and Power
Management” chapter of the software configuration guide. Refer to the appropriate guide for your
software release.
