PairGain 150-1236-54, Руководство пользователя

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Section 150-319-254
Revision 02
Page 23
C. APPLICATIONS USING HIGAIN DOUBLER
EDU-451
1. GENERAL
1.01 For Doubler applications, one or two
Doublers (EDU-451) may be used in the
HDSL loops between the ELU-319 and the ERU-
412. When one doubler is used, the ELU can line
power both the EDU and the ERU. When using two
Doublers in a HDSL loop, the ERU-412 must be
locally powered.
2. POWER CONSUMPTION
2.01
The maximum current drain is the current
drawn from the shelf power supply when it is
at minimum voltage (-42.5 VDC) under a worst case
application. The following analysis assumes a 22
slot PairGain HMS-318 shelf. The worst case
application for the ELU-319 occurs on a loop with
one EDU-451 Doubler and four 3.3 km foot, 0.4 mm
spans. Under these conditions the ELU-319 current
drain from the -42.5 VDC battery is 0.44 A. This CO
current and other related power parameters for this
doubler application are listed in Table 7.
2.02 The maximum ELU-319 power dissipation
is the power that is converted into heat
within the unit. It contributes to the total heat
generated and is used to determine the maximum
number of shelves per bay that do not exceed the
maximum power dissipation density in Watts/sq. ft.
2.03 The thermal loading limitations imposed
when using the ELU-319 in Controlled
Environmental Vaults (CEV) or other enclosures are
determined by applying the ELU-319 power
parameters to the manufacturer requirements for
each specific housing.
TABLE 7. ELU-319, LIST 5D and 6D
POWER PARAMETERS WITH EDU-451
CO
Voltage
Volts
CO
Current
Amperes
Power
Consumption
Watts
ELU Power
Dissipation
Watts
42.50 0.50 21.00 8
48.00 0.44 21.00 8
56.00 0.38 21.00 8
2.04 The power consumption listed in Table 7 is
the total power that the ELU-319 consumes
or draws from its -48 VDC shelf power source. This
parameter is needed when the ELU-319 is located
remote to its serving CO. It determines the battery
capacity required to maintain a stand-by battery
reserve for emergency situations. It thus limits the
maximum number of plugs per remote enclosure.
Use this data to perform other appropriate analysis
on a case by case basis.
2.05 The maximum Current Drain is the
maximum current drawn from the shelf power
supply when it is at its minimum voltage (-42.5 V).
This determines the shelf fusing requirements. The
PairGain HMS-318 ELU-319 shelf is partitioned into
two equal halves, each should be fused at 10 A for a
total of 20 A per shelf. A full shelf containing 22
doubler units slot draws 11 A worse case (5.5 A per
fuse). This is within the 10 A fuse limit.