Figure B-10 Pcm - Sun Microsystems Enterprise 6500 Reference Manual

B.9 Power Supplies
There are two types of power supplies: power/cooling modules (PCMs) and
peripheral power supplies. PCMs provide DC current and cooling air to boards in
the card cage. The peripheral power supply provides current for peripheral devices
(such as a tape or CD-ROM drive) in the media tray.
B.9.1 Power/Cooling Modules (PCMs)
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.
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.
FIGURE B-10
B-16 Sun Enterprise 6500/5500/4500 Systems Reference Manual • April 1998
PCM