Red Hat Server tc3100 User's Guide download pdf (Page 37)

Installation 37

Installation

Circuit breakers must be adequately rated for inrush and operating currents.

Hewlett-Packard recommends magnetic-type circuit breakers, which are capable

of handling large inrush currents for short durations (10 to 12 cycles) and are

rated adequately for steady state currents.

Choosing PDUs

Peak power requirements and PDU capacity affect the number of disk systems

that can be installed in a rack. For example, to install more than four disk systems

in Hewlett-Packard Rack Systems/E (HP Models J1500A(1.96M),

J1501A(1.60M), or J1502 (1.25M)), you must upgrade to 19-inch PDUs.

Besides rack density, the following factors can help you choose PDUs:

■ Redundant power source. To connect redundant power supplies to separate

PDUs, install redundant PDUs.

■ Number of cords to the AC source. Using 30-amp PDRUs instead of 16-amp

PDUs reduces the number of cords to the wall.

■ Future needs. Installing surplus PDU capacity allows you to add disk system

units later.

■ Inrush margins. For installations that require four or more 16-amp PDUs,

Hewlett-Packard recommends HP 30-amp PDRUs (E7681A, E7682A) for

their inherent inrush protection.

■ On/Off switch capability. Some PDU/PDRU options support the use of a

single-point on/off switch. See Figure 12 and Figure 13.

The following tables show how many and what kind of PDU/PDRUs are needed

to install one or more disk systems in an HP rack. Data assumes 220V AC

nominal power and redundant PDU/PDRUs. For nonredundant configurations,

divide the number of recommended PDU/PDRUs by 2.

1 2 ... 32 33 34 35 36 37 38 39 40 41 42 ... 157 158

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Red Hat Server tc3100 User's Guide Page 37