Nortel DMS-100 Series Maintenance Manual page 112

2-18 OPAC maintenance overview
captive screw attached to the faceplate provides positive memory and
conductive coupling to the shelf.
The NTRX44AA provides the following functions:
The NTRX44AA has the following operating blocks:
The relationship between the functional blocks appears in the following
figure.
NTRX44AA functional blocks
–48 V
Inductor
BR
The NTRX44AA uses a 20A QHP77C bracket-mounted power inductor and
six 80-V capacitors that provides 6800µF of capacitance.
Current-limiting startup circuit This circuit limits the inrush current on
startup to eliminate the risk of tripping the feed breaker. A thermistor is the
first to charge the capacitors.
297-8211-550 Standard 05.01 August 1999
termination point for power feeds
filtered battery feed through connector interfaces
soft-start provided by a current-limiting startup circuit to protect against
breaker trip
two fail alarms
inductor
capacitors
current-limiting beginning circuit
alarm circuit
Capacitors
Current-limiting
startup circuit
Alarm circuit
Talk battery
OUT
Alarm module
NTRX41AA