Rectifier MCSU-4 - Fault Finding and Replacement Procedures; System Fault Finding Procedures

Installation, Operation and Technical Manual Rectifier Technologies
158-1872-01 78 19-Feb-14
9. Fault Finding and Replacement Procedures
This section describes in some detail the possible causes for alarms that may occur from
time to time and the procedures that should be followed to clear the alarms and more
importantly, address the problem or cause of the alarm.
It is assumed here that the most that a field maintenance person will do is change a
complete module. It is normally impractical to attempt to repair a particular unit without
test equipment, which is normally only available in the manufacturer's service laboratory.
The recommendation is for spare complete units to be kept on site. This includes a
complete SMR, a MCSU-4 unit, and a MUIB sub-assembly. The fault finding procedures
are presented below.
9.1 System Fault Finding Procedures
The following table outlines suggested procedures to be followed if it is assumed that no
internal repairs of units will be attempted. It is assumed instead that only MCSU-4
adjustments and unit replacement will be performed.
Alarm Condition
Possible Cause
Action Suggested
UNIT OFF
No AC power to SMR
Check AC supply to SMR; if necessary
reset CB supplying SMR
SMR faulty
Replace SMR
Equalise Mode
Equalisation cycle in progress due to
recent AC power failure, periodic or
manual initiation.
No action required
SMR Urgent
All SMRs off due to AC power failure
If possible restore AC power
One or more SMRs off due to faults;
Check Individual SMRs for obvious
problem; replace SMRs if necessary
All SMRs off due to incorrect Inhibit
signal from MCSU-4
Replace MCSU-4
One or more SMRs in Current Limit
Check Current Limit settings and adjust if
necessary; or batteries being recharged
SMR Alarm
Any of the above or non critical problem
with one or more SMRs
Select SMR menu. Check status of
SMRs which are flashing alarm LED.
AC Fail (SMR alarm)
Total AC power failure or AC voltage not
within operating limits
Check AC supply and confirm condition;
If AC is OK replace SMR units if only two
show alarm condition
Cct Breaker
Fuse or CB within PDU has blown or
tripped
Check PDU (Power Distribution Unit)
Wire or connector loose on MUIB
Check MUIB connections and tighten
Battery Switch
Any one of 2 battery switches is open
Close if appropriate
Bad connection to MUIB
Repair connection
Amb Temp High
Ambient Temperature is too high
Reduce temperature – check Air Con.
Temperature sensor is faulty
Check and replace if necessary
Connection to MUIB is faulty
Repair connection
Set point is too low
Check Amb Temp High threshold level
and re-adjust if necessary