User`s guide

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2: Storage Enclosures
Figure 2-6 Environmental Status Modules
Power Supply and Fan Modules
The storage enclosures each have two combined function power/fan units. These units
are mounted in the rear of the enclosure (see Figure 2-7). They pull air through the front
bezel to cool the internal components of the enclosure. The air is exhausted out the rear
of the fan units. For more information on the power/fan units, see “Wiring and Power”
on page 95.
The power/fan units provide power to the other components in the enclosure by
converting incoming AC voltage to DC voltage. The power supplies are redundant: if
one supply fails, the other power supply can keep the enclosure running until the failed
unit can be replaced. Each power/fan unit has the following components on its rear
panel (see Figure 2-7 on page 21):
• Locking lever
• AC power input connector
•Power switch
• Power light
• Fault light
During normal operation, the power light is illuminated. If there is a problem with the
power/fan supply, the fault light comes on.
The fans provide redundant cooling of the enclosure. If one fan unit fails, the other fan
unit runs at a higher speed to compensate for the loss. Each power/fan unit has a fault
Disk expansion enclosure rear panel ESMs