NOTE: For AC power supplies, use only power supplies with the Extended Power Performance (EPP)
label on the back. Mixing PSUs from previous generations of servers can result in a power supply
mismatch condition or failure to power on.
NOTE: When you have more than two GPU cards on your system, you will need two 1100 W power
supply units installed on your system.
Hot spare feature
Your system supports the hot spare feature that significantly reduces the power overhead associated with
power supply unit (PSU) redundancy.
When the hot spare feature is enabled, one of the redundant PSUs is switched to the sleep state. The
active PSU supports 100 percent 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 percent, then the redundant PSU is switched to the
active state.
• If the load on the active PSU falls below 20 percent, 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
available at
Dell.com/
idracmanuals
.
Removing a redundant AC 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 are shipped with your product.
CAUTION: The system requires one power supply unit (PSU) 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.
Follow the safety guidelines listed in the Safety instructions section.
2.
Disconnect the power cable from the power source and from the PSU you intend to remove and
remove the cables from the strap.
NOTE: You may have to unlatch and lift the optional cable management arm if it interferes with PSU
removal. For information about the cable management arm, see the system’s rack documentation.
Steps
1.
Press the release latch.
2.
Holding the PSU handle, pull the PSU out of the PSU bay to release the PSU from the Power
Distribution Board (PDB).
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