150-319-205-05, Issue 5
Functional Description
ELU-319 List 5E and List 6E
January 26, 2000
13
P
OWER
C
ONSUMPTION
WITHOUT
D
OUBLERS
The three most important power parameters of an ELU are its maximum power consumption, its maximum power
dissipation and its maximum current drain. These three parameters for the ELU-319, as a function of the ERU
model and its CPE power option setting, are listed in
Table 7
.
Maximum Power Dissipation
The Maximum Power Dissipation measures the power that is converted into heat that builds up 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 per square foot to comply with GR-63-CORE.
In COs, the maximum power dissipation for open-faced, natural convection-cooled mountings is limited to
134.7 watts per square foot per GR-63-CORE. The footprint of a standard 13-slot, 23-inch ELU-319 List 5E and
List 6E shelf is 7.024 square feet, and the maximum bay dissipation is limited to 946 watts. Use this limit and the
parameters in
Table 7
to determine the maximum number of ELU circuits that can occupy one CO bay.
The thermal loading limitations imposed when using the ELU in a Controlled Environmental Vault (CEV) or other
enclosures are determined by applying its power parameters to the manufacturer's requirements for each specific
housing.
The 48 V Power Consumption is the maximum total power that the ELU-319 List 5E and List 6E consumes or
draws from its -48 V shelf power source. This parameter is needed when the ELU-319 List 5E and List 6E is in a
location remote to the CO it is serving. It determines the battery capacity required to maintain an 8-hour, stand-by
battery reserve for emergency situations. Battery capacity limits the maximum number of line units which can be
installed in a remote enclosure. Use the data in
Table 7
to perform this analysis on a case by case basis.
Maximum Current Drain
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. Use the 42.5 V current data in
Table
7
to determine the shelf fusing requirements for your particular ELU applications.
Table 7.
Maximum Power Parameters for ELU-319 List 5E and List 6E
(1)
(1) Maximum power parameters for ELU-319 List 5E and List 6E on 9 kft, 26 AWG (0.4 mm) loops without
doublers.
ERU Model #
48 V Power
Consumption (W)
Heat Dissipation
(W)
42.5 V Current
(mA)
ERU-412 List 1 and List 2
11
5.0
260
ERU-412 List 1E and List 2E
7.25
4.5
159
This is a worst case situation since it assumes the entire CO is subjected to the maximum
power density. More favorable conditions would permit increasing the number of shelves per
bay without jeopardizing the CO thermal integrity.
