Selecting Server Power Cords - HP ProLiant DL380 Technical White Paper

HP ProLiant DL380 Generation 3 Server High-Density Deployment
Non-Redundant The following examples illustrate how to calculate the number of servers per PDU when using non-
Power
redundant power.
Example
Example
Redundant Power
The server supports a redundant power supply. The power supply for this server automatically senses
input voltage level. Under normal operation, the two power supplies load share with each power
supply supporting 50% of the load of the server. When one power supply or power source fails, the
remaining power is capable of supporting the entire load of the server.
Likewise, when configuring a rack of servers for redundant power feeds, the PDUs should only be
loaded to 50% of its rated capacity while supporting no more than 50% of the load of the rack
under normal operation. If one of the power feeds fails, the PDU would still have sufficient capacity
to support the entire load of the rack.
When planning a configuration with redundant power supplies for redundant feed, the calculations
should be performed as if only one feed was being supplied. Then, the resulting PDUs and power
infrastructure components for the rack should be doubled.
The appropriate server power cord to use depends on the cable management system installed in the
Selecting Server
rack. Generally, the sliding rail cable management system requires a power cord that is 1.83 m (6 ft)
Power Cords
in length. This length provides enough slack for the power cord to route through the cable
management solution.
One high-voltage PDU has a current rating of 24 A. The server has a total input current
rating of 2.3 A at 200 volts.
24 A (PDU current rating)/2.3 A (server total input current rating) = 10.4
This PDU can support a maximum of 10 servers at full server input current ratings.
One low-voltage PDU has a current rating of 24 A. The server has a total input current rating
of 4.9 A at 100 volts.
24 A (PDU current rating)/4.9 A (server total input current rating) = 4.9
This PDU can support a maximum of 4 servers at full server input current ratings.
CAUTION: When loading a PDU in a redundant configuration, never exceed 50% of the rated
capacity of the PDU under normal operation. If the PDUs are loaded beyond 50% and one power
feed or PDU fails, the remaining PDU will trip due to overload and the entire rack will lose power.
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