Power Supply/Fan Assembly Leds - HP 201723-B21 - StorageWorks Modular SAN Array 1000 Hard Drive Maintenance And Service Manual

Power supply/fan assembly LEDs

Each power supply/fan assembly has one LED.
The LED is illuminated when both the power supply and the fan are operational. When a power supply
or fan fault occurs, the LED goes off. If the LED is off, AC power is not present or there is a complete
power supply failure.
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The power-supply-mounted fans cool the chassis by circulating air through the enclosure. The rate at
which air moves (the airflow) determines the amount of cooling. This airflow is a function of fan speed
(rpm). These fans, under the control of the Environmental Monitoring Unit (EMU) or the associated power
supply, can operate at multiple speeds. This ensures that when the enclosure temperature changes, the
fans can automatically adjust the airflow. If one fan operates too slowly or completely shuts off, the
other fan operates at a higher speed. At the same time, the error condition is reported to the user
via the LCD panel on the front of the controller.
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System components and LEDs