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2
1
. GENERAL DESCRIPTION
1.1.
The Westell NPTPA1123 Fuse Panel
provides fused distribution of DC power to
equipment.
The panel has 2 buses, each bus
consisting of 5 GMT style fuse positions and 4
TPA style fuse positions. Alarm circuits are
provided
to
indicate
and
extend
alarm
conditions when faults occur.
1.2.
Input wiring is connected to a high current,
2-hole lug input block located at the rear of the
panel. Each bus has its own completely isolated
inputs, allowing the distribution of two battery
voltages through the same panel.
1.3.
The power is distributed to the load side
equipment through GMT and TPA style fuses.
There are 5 GMT and 4 TPA style fuses per group
and two groups per panel. Each fuse position is
available for installer connection at the rear of the
panel. A designation card is provided for keeping
records of which position is connected to which
equipment and what amperage is to be used.
1.4.
Alarm circuits are provided to alert
service personnel of fault conditions. A fuse
alarm is a blown fuse (GMT or TPA) within a
given bus. A red fuse alarm LED
!
on the
faceplate will illuminate when a fuse alarm
condition is present. As well, the green Normal
Operation LED
will extinguish to signal a fuse
alarm or input power failure and the appropriate
relay contacts will change states. These fuse
panels have common (C), normally open (NO)
and normally closed (NC) terminals for alarms.
Note, the use of the alarm contacts is optional,
if you do not wish to extend the alarms, you
don’t have to do anything with the alarm pins.
The “Normal” condition of the relay exists when
the panel is powered up without any blown
fuses.
The local alarm LEDs are located on the
front of the panel as shown in Figure 1.4.1
LED
SYMBOL
SIGNIFICANCE
GREEN
NORMAL OPERATION
RED
!
BLOWN FUSE
!
!
A
B
V
I
Figure 1.4.1
1.5.
These Fuse Panels are made from 0.050"
steel and painted off-white. Single rack
height
panels are shipped with universal brackets
(1” &
1-1/4
” hole spacing) that will fit both 19" and 23"
wide racks and use only one 1.75" panel space.
The panel has a clear L shaped plastic shield to
protect the wiring connections on the back of the
panel.
2. APPLICATION
2.1.
The NPTPA1123 Fuse Panel is designed
to be used in the rack level distribution of DC
power. They are rack mount panels that
provide fused DC power through two busses;
each bus has 5 GMT style fuses, and 4 TPA
style fuses per bus.
2.2.
The NPGMT family fuse panels are
suitable for installation as part of a Common
Bonding Network (CBN). As well, this family of
fuse panels is suitable for restricted access
locations
in
Network
Telecommunications
Facilities and OSP.
3. CIRCUIT DESCRIPTION
3.1.
Power is connected to the panel through
1/4” stud input blocks (see fig 4.4.1). There is
one set of inputs for each bus. These inputs
are high current terminals with a maximum
continuous current of 120 Amps. There is a
Return (RTN) and Battery (BAT) input for each
bus.
3.2.
Distribution of current from each bus is
provided by GMT and TPA style fuses. Each
bus has 5 GMT fuses and 4 TPA fuses. Each
fuse position is made available at the rear of the
panel via #6 screw terminal blocks. The GMT
fuses for both bus A and bus B are numbered 5
-
53.8