Dell EMC PowerEdge R740xd2 - Power Supply Units; Hot Spare Feature

Figure 117. Installing the internal USB memory key
1 USB memory key 2 USB port
Next steps
1 If removed, install the low prole expansion card riser.
2 If removed, install the air shroud.
3 Install the system cover.
4 Place the system into the rack. For more information, see the Rail Installation Guide available at www.dell.com/poweredgemanuals.
5 Open the drive bays, install all drives, and then close the drive bays.
6 Install the power supply units.
7 Follow the procedure listed in After working inside your system.
8 While booting, press F2 to enter System Setup and verify that the system detects the USB memory key.
Power supply units
NOTE
: For more information, see the PSU specications section.
Hot spare feature
Your system supports the hot spare feature that signicantly 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 eciency. 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 ecient 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 congure 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 www.dell.com/idracmanuals.
Installing and removing system components
143