Section 150-431-114
Release 01
Page 13
B. APPLICATIONS WITHOUT HIGAIN
DOUBLERS (HDU-451)
12. SECTION INTRODUCTION
12.01
This section addresses HLU-431, List 1D
operation without the use of doublers. For
applications without doublers, the HLU-431 is directly
connected to the HRU-412 by the two cable pairs.
13. POWER CONSUMPTION
13.01
The three most important power demands of an
HLU-431, List 1D on the shelf power supply are
its maximum power consumption, its maximum power
dissipation, and its maximum current drain. These three
parameters for the HLU-431, List 1D, on a per-slot and
per-shelf basis, are as follows:
Maximum Power Dissipation:
•
Per Slot = 6 Watts
•
Per Shelf = 84 Watts
Maximum Power Consumption:
•
Per Slot = 14 Watts
•
Per Shelf = 196 Watts
Maximum Current Drain:
•
Per Slot = 0.38 Amps
•
Per Shelf = 5.3 Amps
Note:
The worst case conditions, under which these
parameters were measured, include a 9,000 ft.,
AWG 26 loop, 60 mA of Customer Provided
Equipment (CPE) current, a fully loaded 23"
wide, 14-slot shelf, and a -42.5 V shelf battery
voltage with the HLU-431 4-character display
“OFF.”
13.02
The Maximum Power Dissipation measures the
power that is converted into heat buildup within
the unit. It contributes to the total heat generated in the
space around the unit. It is used to determine the
maximum number of fully loaded shelves per bay that
does not exceed the maximum allowable power dissipation
density in Watts/sq. ft.
13.03
In Central Office locations, the maximum power
dissipation for open-faced, natural convection
cooled mountings is limited to 120 Watts/sq. ft. per
Section 4.2.3 of the NEBS standard TR-NWT-000063.
The footprint of a standard 14-slot 23-inch HLU-431, List
1D shelf is 7.024 sq. ft. Thus, the maximum bay
dissipation is limited to 840 Watts. At 6 Watts per slot,
this limits the number of occupied slots to 140 per bay.
13.04
The thermal loading limitations, imposed when
using the HLU-431, List 1D in a Controlled
Environmental Vault (CEV) or other enclosures, are
determined by applying the HLU-431, List 1D's power
parameters to the manufacturer's requirements for each
specific housing.
13.05
The Maximum Power Consumption is the total
power that the HLU-431, List 1D consumes or
draws from its -48 V shelf power source. This parameter
is needed when the HLU-431 is remotely located to its
serving CO. It determines the battery capacity required to
maintain an 8-hour standby battery reserve for emergency
situations; thus limiting the maximum number of plugs per
line unit’s remote enclosure. Use the above data to
perform this analysis on a case-by-case basis.
13.06
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. A fully loaded shelf draws 5.3
amps worst case, which suggests a 10 amp fuse for this
application.
13.07
Heat baffles should be placed between every
other shelf, in racks containing more than two
shelves. This technique deflects the rack’s heat outward
and reduces thermal stress on the plugs.
14. LOOPBACK OPERATION
14.01
The HiGain system has a family of loopback
options. The most important of these is the
“Smart-Jack” loopback which enables the HRU-412 to
respond to the standard (2/3 in 5) Smart-Jack in-band
loopback codes, and thus emulates the functions of a
standard Network Interface Device (NID). This option can
be ENAbled or DISabled from either the front panel buttons
or the terminal System Settings Menu.
