Cisco ONS 15454 Series Reference Manual page 50

ONS_15454_Reference_Manual_R8.5.x_--_Shelf_and_Backplane_Hardware
Pilot Fuse
The Pilot Fuse in the Fan tray assembly allows you to blow a low rate fuse when the main fuse of the lower
power battery is not installed in the equipment.
CC-FTAs 15454-CC-FTA 800-27558-01 and 15454-CC-FTA 800-27561-01 can automatically generate an
electrical pulse (without external commands) at power on and about every 25-35 minutes in order to drain
extra current from both the batteries. The amount of current and the duration of the pulse that the CC-FTA
can generate, is suitable to blow the fuses listed in the Table 1-25. Similar to CC-FTA, 15454-FTA3-T
800-23907-01 and 800-23907-05 can also operate the pilot fuses mentioned in Table 1-25 when the main
fuse is missing. Unlike CC-FTA, FTA3-T alternatively drains the current from the two batteries every
50-100 msec to feed the fans.
Table 1-25: Pilot Fuse Ratings
Type of Fuse
Bussmann GMT-18/100A 18/100A
Bussmann GMT-1/4A
Bussmann 70E
Bussmann 70F
This is accomplished in the I-temp range (-40°C to +65°C) in either of these conditions:
When the lower power battery is in the 43.0V to 60.0V range and the higher power battery is more
•
than 1V greater than the lower power battery (or)
When the lower power battery is in the 40.0V to 60.0V range and the difference between the two
•
batteries does not exceed 0.5V.
Power and Ground Description
Ground the equipment according to Telcordia standards or local practices.
Cisco recommends the following wiring conventions, but customer conventions prevail:
Red wire for battery connections (-48 VDC)
•
Black wire for battery return connections (0 VDC)
•
The battery return connection is treated as DC-I, as defined in GR-1089-CORE, issue 3.
•
The ONS 15454 has redundant -48 VDC #8 power terminals on the shelf-assembly backplane. The terminals
are labeled BAT1, RET1, BAT2, and RET2 and are located on the lower section of the backplane behind a
clear plastic cover.
To install redundant power feeds, use four power cables and one ground cable. For a single power feed, only
two power cables (#10 AWG, 2.588 mm² [0.1018 inch], copper conductor, 194°F [90°C]) and one ground
cable (#6 AWG, 4.115 mm² [0.162 inch]) are required. Use a conductor with low impedance to ensure circuit
overcurrent protection. However, the conductor must have the capability to safely conduct any faulty current
that might be imposed.
The existing ground post is a #10-32 bolt. The nut provided for a field connection is also a #10 AWG (2.588
mm² [0.1018 inch]), with an integral lock washer. The lug must be a dual-hole type and rated to accept the #6
AWG (4.115 mm² [0.162 inch]) cable. Two posts are provided on the Cisco ONS 15454 to accommodate the
Pilot Fuse
Current rating
1/4A
18/100A
1/4A
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