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LTPH-SM-1052-04
A/B P
S
OWER
OURCES
Each chassis requires one A battery feed and one B battery feed rated at a maximum of 30A total for fully loaded
chassis assemblies capable of driving a full complement of doublers and remote units.
The A/B power feeds provide total backup power for the HXU, HMU, and HFA cards. The HMU, HXU, and
optional HFA have diode-ORed power feeds.
For the HMS-358 List 5 chassis, the line units are powered as a split feed with half of the line units on each battery
feed. A loss of one battery feed forces 14 lines out of service. This reduces the maximum current required per
battery feed for systems with the maximum number of doublers.
For the HMS-358 List 6 chassis, the line units are powered from the backplane through diode-ORed power feeds.
A loss of one power feed will not affect service.
F
USES
System fuses are located in an external fuse tray typically mounted at the top of the CO rack. The HMU reports
all fuse alarms within the HMS-358. Each chassis within the rack must be equipped with A and B fuses for proper
power protection. Depending upon the system configuration, fuse ratings can vary from 5A to 20A. See
and
Table 15 on page 74
operated in the shelf at a particular fuse size. Fuse sizes other than the ones shown may be estimated from the
application environment and interpolated from the table entries.
For a limited power application, ADC offers an A/B fuse panel that provides A/B power redundancy. This fuse
panel allows the lower 15A fuse requirement of the HMS-358 List 1 chassis to be used and still provide redundant
power.
ADC does not recommend configurations in excess of 30A total per shelf.
For fuse selection, refer to
following assumptions:
•
Each chassis has a maximum of 28 lines installed for driving remote units.
•
The maximum number of doublers per chassis is 84.
HMS-358 List 5 and List 6
for information about fuse selection and the maximum number of line units that can be
Figure 43 on page 75
and
July 14, 2002
Figure 44 on page
80. These figures are based upon the
Appendix A - System Specifications
Table 14
73
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