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SCP-PLL724-010-04H
P
C
OWER
ONSUMPTION AND
The three most important power demands of an COLU on the COTS power supply are its maximum power
consumption, its maximum heat dissipation, and its maximum current drain.
and heat dissipation for the COLU on a per slot and per COTS basis.
The worst case conditions under which these parameters are measured include a 15,000 ft., 26 AWG loop,
a fully loaded COTS, and a -42.5 Vdc COTS battery voltage. The remote is assumed to be ringing one line
with a load of 5 REN, with one line off hook. Loop current sink at the COTS is assumed to be 23 mA. Higher
loop current feed than 23 mA restricts the number of COTS in a bay due to heating.
Maximum Heat Dissipation
The maximum heat dissipation measures the power that is converted into heat built up within the COLU. It
contributes to the total heat generated in the space around the COLU. This measurement is used to determine the
maximum number of fully loaded COTS per bay so as not to exceed the maximum allowable power dissipation
density in Watts per square foot.
In CO locations, the maximum heat dissipation for open faced, natural convection-cooled mountings is limited to
134.7 W per square foot per Section 4.1.4 of the NEBS standard GR-63-CORE. The footprint of a standard
16-slot, 23-inch COTS is 7.042 square foot. The maximum bay dissipation is therefore limited to 948.6 W. At
64.0 W per COTS, this limits the number of fully loaded COTS to fourteen per bay with a heat baffle above each
COTS.
ADC recommends that the number of COTS per bay be limited to six, to allow the flexibility to deploy the widest
range of PG-Plus services from each COTS.
This is a worst case situation in that it assumes the entire CO is subjected to the maximum power density.
Conditions other than worst case would permit increasing the number of COTS per bay without
jeopardizing the CO thermal integrity. Due to the chimney effect, ADC recommends you install one
heat-dissipating baffle between every COTS. This action would prevent exceeding the rated operating
temperature of the COLU units.
PLL-724 List 1
H
EAT
Table 1.
Power Consumption and Heat Dissipation
Power
Maximum Heat Dissipation
HDSL Line Power Off
HDSL Line Power On
Maximum Power Consumption
HDSL Line Power Off
HDSL Line Power On
Maximum Current Drain
HDSL Line Power Off
HDSL Line Power On
January 6, 2003
Power Consumption and Heat Dissipation
D
ISSIPATION
Table 1
.
COTS
COLU
Slot
19-inch
23-inch
2.8 W
33.6 W
44.8 W
4.0 W
48.0 W
64.0 W
2.8 W
33.6 W
44.8 W
8.43 W
101.1 W
134.8 W
0.06 A
0.791 A
1.054 A
0.198 A
2.380 A
3.174 A
lists the power consumption
3
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