T640 Cooling System Description; Figure 39: Airflow Through The Chassis - Juniper T640 Hardware Manual

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T640 Cooling System Description

Figure 39: Airflow Through the Chassis

Copyright © 2010, Juniper Networks, Inc.
Table 24: Delta AC Power Supply LEDs (continued)
LED Color
Yellow
OVER
—One per
TEMP
power supply
–
T640 Three-Phase Delta and Wye AC Power Supply Overview on page 57
Troubleshooting the T640 Power System on page 171
T640 AC Power Requirements on page 356
The cooling system components work together to keep all router components within the
acceptable temperature range. Figure 39 on page 61 shows the airflow through the router.
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.
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
61