IBM DS4700 manual DC power supply and fan units, Power supply and fan unit and airflow

Latch

Lever

Figure 6. Power supply and fan unit and airflow

DC power supply and fan units

The DS4700 Express Storage Subsystem (models 70S, 70T, 72S, and 72T) has two removable dc power supply and fan units. Each dc power supply and fan unit contains one dc power supply and two fans. The four fans pull air through the drive from front to back across the drives.

The fans provide redundant cooling, which means that if one of the fans in either fan housing fails, the remaining fans continue to provide sufficient cooling to operate the storage subsystem. The power supplies provide power to the internal components. If one power supply is turned off or malfunctions, the other power supply maintains power to the storage subsystem. To preserve the optimal airflow, do not remove a failed dc power supply and fan unit CRU from the DS4700 Express chassis until you are ready to replace it with a new CRU.

Figure 6 shows a power supply and fan unit and the airflow through the storage subsystem.

Figure 7 on page 15 shows a side view of the dc power supply and fan units (
1).

Note: Although both dc power supply and fan units (left and right) are identical, they are seated in the DS4700 Express chassis in opposite orientations. If the dc power supply and fan unit cannot fully be inserted in the dc power supply and fan unit bay, flip it 180 degree and reinsert it.

14IBM System Storage DS4700 Express Storage Subsystem: Installation, User’s and Maintenance Guide