Sun Microsystems Sun StorEdge T3, Installation, Operation And Service Manual

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Chapter 5 Service 5-7
5.2.2 Power and Cooling Units
The power and cooling unit has two active power sources: standby and primary
power. Standby power, which is used to power the microcontroller 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 alternate AC
power sources for full redundancy.
FIGURE 5-5
Power Cords Connected to the Power and Cooling Units
Caution –
Do not handle the power and cooling unit when the power cord is
connected. Line voltages are present within the power and cooling unit when the
power cord is connected even if the power switch is off.
At the rear of the power and cooling unit is a recessed PC card connector. Do not
touch this connector or allow any metal object to touch it. The power and cooling
unit contains the UPS battery backup. There are no serviceable parts inside this unit.
Power switches