1400 W Dc Power Supply Guidelines And Restrictions - Cisco WS-C2948G-GE-TX Configuration Manual

Chapter 28 Power Management
• Combined mode requires that you install two power supplies in your switch. If you have only one
power supply, and you set the switch to combined mode, the switch places each module in reset
mode.
If the power requirements for the installed modules exceed the power that is provided by the power
•
supplies, the switch displays this message:
Insufficient power available for the current chassis configuration.
If you try to insert additional modules that exceed the power of the power supplies into the switch,
•
the switch places the newly inserted module into reset mode and displays this message:
Module has been inserted and Insufficient power supplies operating.
• If you power down a switch, and you insert an additional module or change the module configuration
so that the power requirements exceed the available power, when you power on the switch again,
one or more modules are placed in reset mode.
If too many powered devices are drawing power from the system, the power to the devices is cut and
•
some devices may power down.
Note A module in the reset mode continues to draw power as long as it is installed in the chassis.

1400 W DC Power Supply Guidelines and Restrictions

This section describes the guidelines and restrictions for using a 1400 W DC power supply in the
Catalyst 4500 series switches:
Do not use the 1400 W DC power supply with any other power supply, even for a hot swap or other
Caution
short-term emergency, because you can seriously damage your switch.
• The 1400 W DC power supply works with a variety of DC sources. The DC input can vary from
300 W to 7500 W. Refer to the power supply documentation that shipped with your power supply
for additional information.
• Supervisor Engine II cannot detect the DC source that is plugged into the 1400 W DC power supply.
If you use the 1400 W DC power supply with Supervisor Engine II, use the set power dcinput
command to set the DC input power. For more information, refer to the Catalyst 4500 Series,
Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Command Reference.
Software automatically adjusts between system power (for modules, backplane, and fans) and PoE.
•
PoE is 96 percent efficient, and system power has only 75 percent efficiency. For example, each 120
W of system power requires 160 W from the DC input.
The 1400 W DC power supply does not support combined mode. If you set the power budget to 2
•
(combined mode), the switch ignores the setting and remains in redundant mode.
The 1400 W DC power supply has a separate power on/off switch for PoE. The power supply fan
•
status is tied to the power supply status so that the status of the PoE switch can be reported to
software. If the power supply fan fails, the display shows the power as faulty, even if the main power
is working properly.
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide
78-15908-01
Understanding How Power Management Works on the Catalyst 4500 Series Switches
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Release 8.2GLX
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