Power Supplies; Power/Cooling Modules; Figure B-9 Pcm - Sun Microsystems Enterprise 3500 System Reference Manual

B.5

Power Supplies

There are three types of power supplies: power/cooling modules (PCMs), auxiliary
peripheral power supply (optional), and peripheral power supply/AC. 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 DVD-ROM drive)
in the media tray. The peripheral power supply/AC provides current for peripheral
devices, and has the AC switch and AC cable socket.
B.5.1

Power/Cooling Modules

FIGURE B-9
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.
B-12 Sun Enterprise 3500 System Reference Manual • August 2001
PCM