HP ProLiant BL280c - G6 Server Introduction Manual page 15

Figure 13 shows a rack configuration of twenty HP DL380 G6 servers receiving power through
redundant power buses. This example is based on the Power Advisor calculations indicated in Figures
11 and 12. The power supplies (PS A and PS B) of each server connect through PDUs to the separate
power buses.
With both power buses active, the power supplies and PDUs evenly share the server load
(approximately 13.8 A per bus). While a 24-amp PDU could handle the load during normal
conditions, a PDU would need to distribute 27.6 amps required by all the servers if one bus should
fail. For this reason, a PDU on a redundant power bus should never provide more than 50 percent of
its rated capacity in normal operation. In the example shown in Figure 13, the 40-amp PDUs are
required and provide headroom for additional equipment upgrades.
Figure 13. 42U rack configuration of HP ProLiant DL380 G6 servers with redundant power buses
Physical Configuration
11 thru 20
The Power Advisor indicates that the cooling requirement for the rack configuration shown in Figure
13 would be 17887.2 BTUs/hr (894.36 x 20). This level of BTU generation may require special
cooling considerations such as controlled air, forced air, or chilled-water systems.
NOTE
For more information on power distribution strategies and three-
phase power refer to the white paper "Power Basics for IT
Professionals" at
http://h20000.www2.hp.com/bc/docs/support/SupportManual/
c01234421/c01234421.pdf
40A
PDU
DL380 G6
servers
1 thru 10
DL380 G6
servers
13.8 A
Bus A
(208 VAC)
Normal operation
Functional Block Diagram
PS A PS B
DL380 G6
servers
1 thru 10
PS A
PS B
DL380 G6
servers
11 thru 20
Redundant operation (Bus A failure)
40A
PDU
27.6 A
13.8 A
Bus B
(208 VAC)
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