Compaq ProLiant BL e-Class System Overview and Planning

Compaq ProLiant BL e-Class System Overview and Planning 23
Failure scenario 2
If the AC source for PDU 1 fails (or PDU 1’s power cord is unplugged), PDU 2 must
now support the full current load of all enclosures. PDU 2’s output circuit breakers each
support a 10-A enclosure, which is within the breakers’ rated specifications. However,
this combined 10 + 10 + 10 + 10 = 40-A load exceeds PDU 2’s input rating of 24 A. This
may cause PDU 2’s input breaker to trip or PDU 2’s AC source to fail, resulting in power
loss to all enclosures.
Remedy
Use two high-line voltage PDUs (such as P/N 207590-D72) instead of low-line PDUs. At
high-line, each enclosure only requires 5 A, so power re-distribution after a power supply
failure is still within limits (see Figure 12).
Figure 12. Redundant PDU configuration with four enclosures (high-line)
Choosing a Power Solution
Compaq offers several PDUs designed for use in high-volume rack deployments. Compaq PDUs
are equipped with circuit breakers that provide over current and surge protection for connected
devices to help prevent electrical surges and external equipment malfunction. Compaq offers a
variety of PDUs that support both high- and low-voltage applications. Table 2 lists PDU options
.