T640 Three-Input 240-A Dc Power Supply Leds; Input; Table 19: Components Powered By Each Three-Input 240-A Dc Power Supply; Table 20: Fault Tolerance - Juniper T640 Hardware Manual

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T640 Three-Input 240-A DC Power Supply LEDs

Copyright © 2010, Juniper Networks, Inc.
Table 19: Components Powered by Each Three-Input 240-A DC Power
Supply Input

Input

Three-Input Mode
T640-SIBs, T-CBs, fan trays, Routing
INPUT 0
Engines, and FPCs in slots
FPC1
FPCs in slots
INPUT 1 FPC2
This input is not supported in
INPUT 2
mode.
Three-Input 240-A DC Power Supply Load Sharing and Fault Tolerance
When the router is operating normally and both power supplies are switched on, load
sharing between them occurs automatically. When one power supply fails or is turned
off, the other power supply immediately assumes the entire electrical load for the system.
A single power supply can provide full power for as long as the router is operational. Table
20 on page 53 describes the behavior of the power supply if one of the inputs fails.

Table 20: Fault Tolerance

Redundancy
Nonredundant power supply
Redundant power supplies
T640 Power System Description on page 49
Powering On a DC-Powered T640 Router on page 130
Maintaining the T640 Power Supplies on page 159
LEDs on each power supply faceplate (see Figure 29 on page 54) indicate the status of
the power supply. In addition, a power supply failure triggers the red alarm LED on the
craft interface. Table 21 on page 54 describes the functions of the power supply LEDs.
Chapter 3: T640 Router Hardware Component Overview
and
FPC0
through
FPC7
2–INPUT
Fault Tolerance When One Input Fails or is Disconnected
If this input fails, the router shuts down.
NOTE: We recommend that you install redundant power
supplies.
If an input on one power supply fails, the other power supply
assumes the electrical load for all inputs. If one input on the other
power supply is not functional, the router shuts down.
53