Power/Cooling Modules

Figure B-9 PCM

The DC power to the centerplane is supplied by one or more PCMs. Each PCM also provides cooling air for two board slots. If a slot contains a board, the adjacent PCM slot must contain a PCM to supply cooling air.

The system has a maximum capacity of three PCMs. The slot above the peripheral power supply/AC may have either a PCM or a fan tray.

Current from individual PCMs is shared on the centerplane.

With automatic system reconfiguration (ASR), a PCM can be taken offline and replaced without halting the system. There are two restrictions:

1. The remaining power/cooling modules must provide sufficient electrical power. As a general rule, the number of boards must be less than half the number of PCMs.

2. The PCM should be replaced quickly so that any adjacent boards will not overheat from lack of fan cooling.