NOTE: Titanium PSU is nominally rated for 200 VAC to 240 VAC input only.
The 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.
NOTE: If two PSUs are used, they must be of the same type and have the same maximum output
power.
Hot-spare feature
Your system supports the hot-spare feature that significantly reduces the power overhead associated
with PSU redundancy.
When the hot-spare feature is enabled, a redundant PSU is switched to a sleep state. The active PSU
supports 100 percent of the load, thus operating at higher efficiency. The redundant PSU in the sleep
state monitors output voltage of the active PSU. If the output voltage of the active PSU drops, the
redundant PSU in the sleep state returns to an active output state.
The active PSU can also activate a sleeping PSU if having both PSUs active is more efficient than having
the redundant PSU in a sleep state. The PSU defaults are to wake both PSUs if the load on the active PSU
is greater than 50 percent and to sleep the redundant PSU if the load falls below 20 percent.
You can configure the hot-spare feature using the iDRAC settings. For more information about iDRAC
settings, see the iDRAC User's Guide at dell.com/support/home.
Removing AC power supply unit
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 PSU for normal operation. On power-redundant systems,
remove and replace only one PSU at a time in a system that is powered on.
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.
1. Disconnect the power cable from the power source and the PSU you intend to remove and remove
the cables from the strap.
2. Press the release latch and slide the PSU out of the chassis.
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