Sun Microsystems StorEdge T3+, Service Manual

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7-1
C H A P T E R
7
Power and Cooling Unit Assemblies
This chapter describes how to replace the power and cooling unit and monitor the
UPS battery. The chapter contains the following sections:
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Section 7.1, “Power and Cooling Unit” on page 7-1
■
Section 7.2, “Power and Cooling Unit LEDs” on page 7-2
■
Section 7.3, “Removing and Replacing a Power and Cooling Unit” on page 7-4
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Section 7.4, “UPS Battery” on page 7-6
7.1 Power and Cooling Unit
The power and cooling unit has two active power sources: standby and primary
power. Standby power, which is used to power the micro controller on the
interconnect card, is activated when AC power is present. Primary power, which is
used to power all remaining circuits and disk drives, is activated when AC or
battery power is present and the power switch is on.
Each power and cooling unit has a power switch in the rear upper center of the unit.
Turning off the power on a power and cooling unit affects only that power and
cooling unit. Therefore, to power off all primary power to the unit, both power
switches on both power and cooling units must be turned off. After the switches are
turned off, system primary power will not actually turn off until the controller has
performed an orderly shutdown, including writing any data cache to disk. This
process can take up to two minutes.
Separate power cords are used for the connector on each power and cooling unit to
provide redundant cabling. The power cords need to be connected to separate AC
power sources for full redundancy.