16
R/Evolution 2000 Series Troubleshooting Guide • May 2008
Power Supply Unit
Each 750-Watt, AC power supply unit (PSU) is auto-sensing and runs in a load-
balanced configuration to ensure that the load is distributed evenly across both
power supplies.
Cooling Fans
The cooling fans are integrated into each of the power-and-cooling module FRUs.
Each module contains two fans mounted in tandem (series). The fans are powered
from the +12V common rail so that a single failed power supply still enables all
fans to continue to operate.
The fans cannot be accidentally removed as they are part of the power-and-cooling
module. Removing this module requires the disengagement of a captive panel
fastener and the operation of an ejector lever to remove it from the chassis.
Should one fan fail in either module, the system continues to operate indefinitely. In
addition, the fan system enables the airflow pattern to remain unchanged and there
is no pressure leak through the failed fan since there are always two fans in tandem,
and they are sealed to each other through a calibrated cavity. Should a power-and-
cooling module be turned off or unplugged, the fans inside the module continue to
operate at normal capacity. This is accomplished by powering each fan from a
power bus on the midplane.
The fans’ variable speed is controlled by the controller modules through an I
2
C
interface. The fans also provide tachometer speed information through the I
2
C
interface. Speed control is accomplished through the use of speed commands issued
from the controller module. The controller module has one temperature sensor at the
inlet port of the controller to sense the exhaust air temperature from the disk drives.
Should the controller module sense a rise in temperature, it can increase fan speed
to keep the disk drive temperatures within limits.
Balanced cooling for all of the drives is accomplished through the use of two
mechanisms.
■
Tuned port apertures in the midplane placed behind each drive carrier slot
■
The use of a cavity behind the entire surface of the midplane (side-to-side and
top-to-bottom) that acts as an air pressure equalization chamber. This chamber is
commonly evacuated by all of the fans.
In this way the amount of mass flow through each drive slot is controlled to be the
same slot to slot.
Содержание 2000 Series
Страница 1: ...2000 Series Troubleshooting Guide P N 83 00004287 12 Revision A May 2008 ...
Страница 18: ...18 R Evolution 2000 Series Troubleshooting Guide May 2008 ...
Страница 34: ...34 R Evolution 2000 Series Troubleshooting Guide May 2008 ...
Страница 64: ...64 R Evolution 2000 Series Troubleshooting Guide May 2008 ...
Страница 78: ...78 R Evolution 2000 Series Troubleshooting Guide May 2008 ...