Hot spare featureYour system supports the Hot Spare feature that significantly reduces the power overhead associatedwith power supply redundancy.When the Hot Spare feature is enabled, a redundant power supply is switched to a sleep state. The activepower supply supports 100% of the load, thus operating at higher efficiency. The redundant power supplyin the sleep state monitors output voltage of the active power supply. If the output voltage of the activepower supply drops, the redundant power supply in the sleep state returns to an active output state.The active power supply can also activate a sleeping power supply if having both power supplies active ismore efficient than having the redundant power supply in a sleep state. The power supply defaults are towake both power supplies if the load on the active power supply is greater than 50% and to sleep theredundant power supply if the load falls below 20%.You can configure the Hot Spare feature using the iDRAC settings. For more information on iDRACsettings, see the iDRAC8 User's Guide at Dell.com/esmmanuals.Removing an AC power supply unitPrerequisitesCAUTION: Many repairs may only be done by a certified service technician. You should onlyperform troubleshooting and simple repairs as authorized in your product documentation, or asdirected by the online or telephone service and support team. Damage due to servicing that isnot authorized by Dell is not covered by your warranty. Read and follow the safety instructionsthat came with the product.CAUTION: The system requires one power supply unit (PSU) for normal operation. On power-redundant systems, remove and install only one PSU at a time in a system that is powered on.NOTE: You may have to unlatch and open the optional cable management arm if it interferes withpower-supply removal. For information about the cable management arm, see the system’s rackdocumentation.1. Ensure that you follow the Safety instructions.Steps1. Disconnect the power cable from the power source and from the PSU you intend to remove.2. Remove the cables from the strap on the PSU.3. Press the release latch.4. Holding the PSU handle, pull the PSU out of the PSU slot bay to release the PSU from the PowerDistribution Board (PDB).120
