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Appendix A - Specifications
P
C
OWER
ONSUMPTION
The three most important power parameters of an H4TU-C are its maximum power consumption, maximum
power dissipation, and maximum current drain.
Table 20
describes line-powered and locally powered (remote) circuits on the maximum reach condition (34 kft.)
using 26 AWG wire.
Number of
Remote Power
Doublers
Source
None
Locally powered
None
Line-powered
1
Locally powered
1
Line-powered
2
Locally powered
2
Line-powered
M
P
AXIMUM
OWER
The maximum power dissipation measures the power converted into heat which 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.
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. Use this limit and the parameters in
determine the maximum number of H4TU-C circuits that can occupy one CO bay.
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.
The thermal loading limitations imposed when using the H4TU-C 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 Vdc power consumption is the maximum total power that the H4TU-C consumes or draws from the shelf
power source. This parameter is needed when the H4TU-C is in a location remote to the CO it is serving. It
determines the battery capacity required to maintain an 8-hour, standby battery reserve for emergency situations.
Battery capacity, therefore, limits the maximum number of line units which can be installed in a remote enclosure.
Use the data in
Table 21
60
Table 20. H4TU-C Power Parameters
-48 Vdc Power Consumption
(Watts)
Typical
Maximum
7.6
8.4
11.0
12.1
14.6
16.1
20.0
22.0
26.7
29.4
32.9
36.2
D
ISSIPATION
to perform this analysis.
September 12, 2003
Heat Dissipation (Watts)
Typical
Maximum
5.9
6.4
6.2
6.8
6.6
7.2
7.1
7.8
8.4
9.2
9.3
10.3
Table 21 on page 61
LTPH-UM-1031-03, Issue 3
-42.5 Vdc Current (mA)
Typical
Maximum
179
197
259
285
344
378
471
518
628
691
774
852
to
H4TU-C-319 List 1
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