Juniper T640 Hardware Manual page 191

Copyright © 2010, Juniper Networks, Inc.
The current sharing between DC power supplies relies on equal voltages at the input
terminals of the power supplies. However, if the voltages do not match, the router
operates normally as long as the DC input voltages are within the operating range
provided in "T640 DC Power System Electrical Specifications" on page 347.
For the three-input 240-A DC power supplies in
160-A DC power supplies, system power is divided into two load zones. One load
zone consists of
INPUT 0
of and . Load sharing occurs between the two power supplies for each
PEM0 PEM1
load zone. Therefore, the input voltage for the inputs in each load zone must be equal
in both power supplies for current sharing. For example, the input voltage for
of and the input voltage for
PEM0
sharing to occur within that load zone.
For the four-input 240-A DC power supplies, system power is divided into four load
zones. One load zone consists of
zones consist of
INPUT 1
occurs between the two power supplies for each load zone. Therefore, the input
voltage for the inputs in each load zone must be equal in both power supplies for
current sharing. For example, the input voltage for
voltage for of
INPUT 0 PEM1
that load zone.
For further description of the output from the commands, see the Junos OS System
Basics and Services Command Reference.
For AC-powered routers, the output is similar to the following:
user@host> show chassis environment pem
PEM 1 status:
State
Temperature
AC Input:
DC Output
FPC 0
FPC 1
FPC 2
FPC 3
FPC 4
FPC 5
FPC 6
FPC 7
SCG/CB/SIB
Chapter 15: Maintaining T640 Router Hardware Components
2–INPUT
of and . The other load zones consist of
PEM0 PEM1
of
INPUT 0 PEM1
INPUT 0 of PEM0
, and of
INPUT 2 INPUT 3 PEM0
must be the same for current sharing to occur within
Online
33 degrees C / 91 degrees F
OK
Voltage(mV) Current(mA)
55183 7056
55633 7018
55533 5187
55533 7081
55508 6612
55791 7337
55675 2593
55608 7600
55308 5600
mode and the two-input
INPUT 1
INPUT 0
must be the same for current
and PEM1 . The three other load
and . Load sharing
PEM1
INPUT 0 of PEM0 and the input
Power(W) Load(%)
389 51
390 52
288 38
393 52
367 48
409 54
144 19
422 56
309 25
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