Figure 5-44 Dc Pems Installed Behind The Air Intake Plenum - Cisco MGX MGX 8800 Hardware Installation Manual

Chapter 5 Installing the Cisco MGX Switch or Gateway
Step 4 If you are installing the exhaust plenum in a 19-inch cabinet, attach the rear-mounting brackets to the
rack, and use screws to secure the fan tray to the rear-mounting brackets.
Install the DC PEM(s)
Warning Before performing any of the following procedures, ensure that power is removed from the DC
circuits. To ensure that all power is removed, locate the circuit breakers or fuses on the DC power
lines that service the DC circuits. Turn OFF the DC power line circuit breakers and remove the DC
power line fuses. Statement 322
Warning Before working on a system that has an On/Off switch, turn OFF the power and unplug the power cord.
Statement 1
Never install an AC power module and a DC power module in the same chassis. Statement 264
Warning
Warning Before working on a chassis or working near power supplies, unplug the power cord on AC units;
disconnect the power at the circuit breaker on DC units. Statement 12
For a DC-powered system, install the DC PEMs at the back of the air intake plenum. Tighten the captive
screws to attach the DC PEM to the component.
If you install only one DC-PEM, install it on the bottom, as viewed from the rear of the air intake plenum.
(See
Figure 5-44
-48 V DC
-48 V DC
Releases 2 - 5.2, Part Number OL-4545-01, Rev. H0, May 2006
Figure 5-44.)
DC PEMs Installed Behind the Air Intake Plenum
Secondary PEM
RT N
50A
-48 V
-48 V DC
50A
J1
J2
50A RT N
-48 V
-48 V DC
50A J1
J2
Primary PEM
RT N
-48 V
-48 V DC
50A
DC
RT N
-48 V
-48 V DC
50A
DC
Cisco MGX 8800/8900 Series Hardware Installation Guide
Installing the MGX 8950 Switch
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