Power Supply Units; Hot Spare Feature; Removing A Redundant Power Supply Unit - Dell PowerEdge R330 Owner's Manual

Power supply units

Your system supports 350 W AC redundant power supply units (PSUs).
NOTE: If two PSUs are used, they must be of the same type and have the same maximum output
power.
When two identical PSUs are installed, the PSU configuration is redundant (1 + 1). In redundant mode,
power is supplied to the system equally from both PSUs to maximize efficiency.
When only one PSU is installed, the PSU configuration is non-redundant (1 + 0). Power is supplied to the
system only by the single PSU.
In a non-redundant configuration, install a PSU blank in the empty PSU slot.

Hot spare feature

Your system supports the hot spare feature that significantly reduces the power overhead associated with
power supply redundancy.
When the hot spare feature is enabled, one of the redundant PSUs is switched to the sleep state. The
active PSU supports 100% of the load, thus operating at higher efficiency. The PSU in the sleep state
monitors output voltage of the active PSU. If the output voltage of the active PSU drops, the PSU in the
sleep state returns to an active output state.
If having both PSUs active is more efficient than having one PSU in the sleep state, the active PSU can
also activate the sleeping PSU.
The default PSU settings are as follows:
• If the load on the active PSU is more than 50%, then the redundant PSU is switched to the active state.
• If the load on the active PSU falls below 20%, then the redundant PSU is switched to the sleep state.
You can configure the hot spare feature by using the iDRAC settings. For more information about iDRAC
settings, see the Integrated Dell Remote Access Controller User's Guide at Dell.com/idracmanuals.

Removing a redundant power supply unit

Prerequisites
CAUTION: Many repairs may only be done by a certified service technician. You should only
perform troubleshooting and simple repairs as authorized in your product documentation, or as
directed by the online or telephone service and support team. Damage due to servicing that is
not authorized by Dell is not covered by your warranty. Read and follow the safety instructions
that came with the product.
CAUTION: The system requires one power supply for normal operation. On power-redundant
systems, remove and replace only one power supply at a time in a system that is powered on.
1. Ensure that you follow the
2. Disconnect the power cable from the power source.
3. Disconnect the power cable from the power supply unit (PSU) and remove the straps that bundle
and secure the system cables.
Safety instructions.
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