Compaq BL10e - HP ProLiant - 512 MB RAM Update Manual page 12

ISS Technology Update
HP BladeSystem c-Class power structure
The BladeSystem c-Class architecture advances to a level where each enclosure is responsible for its own power, independent
of other enclosures. No longer do we have physically separate enclosure subsystems (power and server), bus bars, or DC
power cables with in-use service complexities (Figure 4-2). Complete power integration negates the previous need for AC and
DC breakers at multiple stages of an external power distribution subsystem.
Figure 4-2. HP BladeSystem c-Class power connectors
HP BladeSystem c7000 enclosure
Each c7000 and c3000 enclosure connects directly to the customer's AC power infrastructure with industry-standard power
cords. The power supply modules installed into each enclosure convert AC power to 12 VDC for distribution inside each
respective enclosure. There are no separate power enclosures, external bus bars, or DC power cables to buy, install, or service.
Electronic fuse circuits integrated into the c-Class enclosures insure equipment protection and fault isolation should one occur.
This provides a high degree of safety and availability. With no physically separate subsystems to connect/disconnect or
service, there is no requirement for conventional circuit breakers.
HP BladeSystem c-Class's integrated enclosure designs have advantages in several areas:
• Lower cost: The integration reduces the cost compared to solutions with multiple external subsystems. The HP BladeSystem
c-Class enclosure costs are kept lower by designs that avoid using conventional circuit breakers. No system design, service,
or safety considerations mandate the presence of such circuit breakers on c-Class enclosures, so no real advantage would be
gained by their addition.
• Higher reliability/Mean Time Between Failure (MTBF): An integrated system design without the need for conventional circuit
breakers local to the enclosure will have higher reliability and MTBF than that same system with circuit breakers included. This
would factor into a lower Total Cost of Ownership over time.
• Human error avoidance: Conventional circuit breakers offer the opportunity to manually de-energize the "wrong" breaker,
prompting an unintentional major loss of service. Enclosure designs with no requirement for conventional circuit breakers
lessen the opportunity for unintentional outages.
Incorporating an unnecessary local circuit breaker on the c-Class enclosure could potentially cause a dangerous safety
misunderstanding or oversight. A circuit breaker can only de-energize power downstream of the breaker itself. A local circuit
HP BladeSystem c3000 enclosure
Item Description
1 AC power connectors (6)
Volume 6, Number 7
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