HP Array Controller HSG V8.7 Software - Manual (Page 163)

Enclosure Blowers
UltraSCSI RAID Enclosure 8–3
• If a blower error condition is caused by only one defective blower
per blower bank (see Figure 8–1), the EMU does not initiate a
power shut down.
Function and Operation
Cooling enclosure components is accomplished by pulling air in
through the front of each component, over the internal circuitry,
through the backplane, and exhausting it out the rear of the enclosure.
The +12 V dc is required for blower operation and is available on
each of the backplane blower connectors. Blower status and speed
control signals are also on these connectors and are routed to the
EMU and PVA.
A blower guide pin ensures connector alignment when installing a
blower. A combination of blower connector and mounting tabs
provides positive mating of the blower with the blower plenum.
If an error condition involving the blowers, intake air temperature, or
exhaust air temperature exists, the EMU can cause all blowers to
switch into high-speed, increasing air flow through the enclosure.
Conditions that might cause this change in blower speed include:
• Removing a blower
• A blower operating too slowly
• A stalled blower
• The intake (EMU) air temperature is within 4°C (7°F) of the
sensor_1 setpoint. For example, if the setpoint is 35°C (95°F), the
blowers will switch to high-speed at 31°C (88°F).
• The exhaust (backplane) air temperature is within 4°C (7°F) of
the sensor_1 or sensor_2 setpoint. For example, if the setpoint is
35°C (95°F), the blowers will switch to high-speed at
31°C (88°F).