HP 3000 Enterprise Virtual Array - Manual (Page 87)

Storage System Hardware Components
87 Enterprise Virtual Array 3000 User Guide
The nominal output of each power supply is 499 W, with a peak output of 681 W.
A single power supply can support an enclosure with a full complement of disks,
blowers, EMU, and I/O module.
The power supply circuitry provides protection against:
■ Overloads
■ Short circuits
■ Overheating
Power supply status and diagnostic information is reported to the EMU with
voltage, current, and temperature signals.
See “ Regulatory Notices and Specifications ” on page 139 for the enclosure power
specifications.
Temperature Sensing
The power supply temperature sensor provides a temperature range signal to the
EMU. The EMU uses this signal to set the blower speed.
The power supply internal temperature can also set the speed of the blower. The
higher the power supply temperature, the faster the speed of the blower. Should
the power supply temperature exceed a preset value, the power supply
automatically shuts down.
Blowers
The blower mounts on the rear of the power supply. A power supply connector is
the interface between the blower and the enclosure for:
■ Speed control to the blower
■ Blower speed to the EMU through the power supply
■ Power supply high speed enable
■ Blower operating voltage
The power-supply-mounted blowers cool the enclosure by circulating air through
the enclosure and the elements. The rate at which air moves (the air flow)
determines the amount of cooling and is a function of blower speed (rpm). These
blowers, under the control of the EMU or the associated power supply, can operate
at multiple speeds. This ensures that when the enclosure temperature changes the
blowers can automatically adjust the air flow.