Service Manual

GSM-204-323
The outdoor power supply module (TOPSM)
31st Oct 01
Tech. 4–28
Technical Description: Horizon macro outdoor
CONTROLLED INTRODUCTION
68P02902W02-A
Monitoring
Internal
Internal TOPSM circuits monitor for the following:
 –55 V output voltage regulation.
 The –55 V output is also regulated to provide temperature compensation
for the float charging of the internal batteries (battery backup) in the range
–52.88 V at 40 C to –56.72 V at 0 C.
 Overvoltage protection – provides shutdown if the output voltage exceeds
–59.9 V.
 Overcurrent protection – provides constant current limiting at 22 to 24 A,
unless output voltage drops below 39.6 V, when the output current will fold
back to between 3 and 8 A.
 Enable control of TOPSM from the control and alarm board.
External
The control and alarm board monitors common alarm signals generated by the
changeover relays fitted within the TOPSMs. The possible alarms are:
 Mains input fail - This alarm is active if all the fitted TOPSMs lose their
input supply or the input drops below their operating minimum value.
 DC output fail - This alarm is active if the output from one or more fitted
TOPSMs fails, or goes outside the preset tolerance level.
Alarm conditions generated by the TOPSM may be detected by one of the red
LEDs being lit, or by the dc output fail and mains input healthy LEDs being unlit.
Protection
circuits
Activation of the protection circuits causes the TOPSM to shut down. During a
shutdown, the output circuits of the malfunctioning TOPSM are isolated and its
output healthy LED is switched off. The malfunctioning TOPSM informs the
control and alarm board of the shutdown condition. An alarm signal is also
activated and sent to the control and alarm board if all TOPSMs detect loss of
ac input voltage. After an alarm condition has ceased, normal TOPSM operation
is automatically restored.
Thermal
protection
The TOPSM is provided with additional internal thermal protection. If the
ambient temperature of the TOPSM exceeds a safe level then it shuts down,
causing an alarm message to be sent to the control and alarm board. Normal
TOPSM operation resumes after the temperature returns to a safe level.