IBM BladeCenter 8677 - Manual (Page 32)

Each pair of power modules is redundant. If either power module fails, the
remaining power module continues to supply power, but there is no redundancy; the
failed power module must be replaced as soon as possible.
Important:
1. The power modules in a pair must match each other in capacity (wattage,
amperage, and so forth).
2. In a pair of power modules, a power module that is not connected to an ac
power source creates a non-redundant condition.
To provide true redundant power, BladeCenter power modules 1 and 3 must
connect to a different ac power source than power modules 2 and 4. Connect
BladeCenter power modules 1 and 3 to a different PDU than power modules 2 and
4; then, connect each PDU to an ac power source (building power source or service
entrance) that is controlled by a separate circuit breaker.
Blower modules
Your BladeCenter unit comes with two hot-swap blowers for cooling redundancy.
The blower speeds vary depending on the ambient air temperature at the front of
the BladeCenter. If the ambient temperature is 72°F or below, the BladeCenter
blowers will run at 30% of their maximum rotational speed, increasing their speed
as required to control internal BladeCenter temperature. If the ambient temperature
is above 72°F, the blowers will run at 80% of their maximum rotational speed,
increasing their speed as required to control internal BladeCenter temperature. If a
blower fails, the remaining blower continues to cool the BladeCenter unit and blade
servers.
Important: Replace a failed blower as soon as possible, to restore cooling
redundancy (see the
Hardware Maintenance Manual and Troubleshooting Guide on
the BladeCenter Documentation CD for instructions).
Installing a module
The following illustration shows how to install a power module, management
module, or I/O module in the rear of the BladeCenter unit. See the
Hardware
Maintenance Manual and Troubleshooting Guide on the BladeCenter
Documentation CD for information about replacing a blower module.
Before you begin, read the documentation that comes with your option.
18 BladeCenter Type 8677: Installation and User’s Guide