T640 Cooling System Description; Airflow - Juniper T640 Hardware Manual

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T640 Cooling System Description

Airflow

Copyright © 2013, Juniper Networks, Inc.
Table 35: Delta AC Power Supply LEDs (continued)
LED Color
Yellow
OVER
—One per
TEMP
power supply
–
T640 Three-Phase Delta and Wye AC Power Supply Description on page 71
T640 LED Overview on page 200
Troubleshooting the T640 Power System on page 207
T640 AC Power Requirements on page 437
The cooling system components work together to keep all router components within the
acceptable temperature range. The host subsystem monitors the temperature of the
router components. When the router is operating normally, the fans function at lower
than full speed. If a fan fails or the ambient temperature rises above a threshold, the
speed of the remaining fans is automatically adjusted to keep the temperature within
the acceptable range. If the ambient maximum temperature specification is exceeded
and the system cannot be adequately cooled, the Routing Engine shuts down some or
all of the hardware components.
Airflow on page 75
Fan Trays on page 76
Air Filters on page 77
Power Supply Cooling System on page 77
Figure 47 on page 76 shows the airflow through the router.
Chapter 3: T640 Router Hardware Component Overview
State Description
On steadily Power supply has exceeded
recommended temperature.
Off If the DC OK
steadily, this LED indicates that
power supply is within the
recommended temperature.
and AC OK are on
75