Alcatel 7750 SR-12, Installation Manual

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7750 SR-12 Overview
7750 SR-12
Page 29
C
OOLING
S
YSTEM
The 7750 SR-12 system is cooled by hot-swappable impeller (fan) trays. A minimum of two
impeller trays must always be installed and fully operational while the SR-12 is powered up. A
third tray can be installed for redundancy. Each tray houses two impellers. The trays are accessed
from the rear of the chassis and are interchangeable in any tray slot. If only 2 impeller trays are
installed, a filler panel must be installed in the redundant slot for proper cooling.
The impellers pull air through the system from front-filtered intake vents, across the IOMs and SF/
CPMs, and exhausts the air through rear vents. The impellers spin at high speed during system
initialization and then slow down to normal operating speed when system initialization is
complete. The fans gradually increase to full speed when the operating temperature rises above
122° F (50° C).
The 7750 SR-12 cooling system consists of the following components:
• Up to 3 trays with two impellers (a minimum of 2 trays is required).
• One air filter.
The cooling system components work together to keep the internal components within the
acceptable temperature range.
The status indicator LEDs for the impeller trays are displayed on the active CPM front panel,
labelled Fan Status (
Figure 3 on page 19 ). A green LED indicates normal operation. The LED is
amber if there is an impeller failure or unlit if there is no power to a tray or a tray is not installed in
the slot.
The 7750 SR-12 chassis is shipped with three factory-installed trays. The entire tray must be
replaced if an impeller fails.
Table 6: AC Power Rectifier Features
Key Description
1 Power supply handle (shown in locked position).
2 Power supply LEDs. See AC Power Supply Module LEDs on page 112 .