IBM TotalStorage SAN256N Director 2045-N16, Installation And Maintenance Manual, Page: 37 / 157

Chapter 2. SAN256N director components
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Each power supply assembly has two front panel LED indicators, that indicate whether
the VAC input voltage and the DC voltage output are within specification.
Figure 12. Power supply assembly
Upper fan assemblies
Three fan module assemblies, located in the upper rear of the chassis, provide the
cooling capability for the SAN256N director and airflow around the PCB modules (in
particular, the TFIO blades) by pushing air out of the chassis. The upper portion of the
chassis is cooled by a push-pull airflow drawn from the lower air inlets, located at the
front and sides of the chassis, and exhausted at the top of the chassis rear.
Each of the upper fan assemblies are powered by 48 Volts DC and provide up to 380
cfm per fan assembly. As a universal fan assembly, any of the three fan modules can be
replaced with the same fan module. In the event of a single fan failure, the remaining
fans increase speed to a higher operating RPM to compensate for the single fan failure.
Each upper fan assembly consists of two fans mounted vertically in a pull-out module.
The fan modules are interchangeable.
DC Indicator
Front View
Rear View
I/O Connector
AC Indicator AC Input
DC On/Off
Receptacle
Power Switch