Mcsu-4 Fault Finding And Repair Procedures - Rectifier RT9- 24V Installation, Operation And Technical Manual

Installation, Operation and Technical Manual
Alarm Condition
Battery Disch
SMR Comms Fail
AC Volt Fault
(System alarm)
AC Freq Fault
Batt I-Limit
Batt Sym Alarm
Earth Leak Alarm
(Only on systems
fitted with MUIB3)

9.2 MCSU-4 Fault Finding and Repair Procedures

In addition to performing a supervisory function by monitoring output voltage and current
and the various system alarms, the MCSU-4 also performs a voltage control function in
order to achieve battery charging current control, battery temperature compensation,
battery equalisation and active current sharing.
To control current to the lowest battery voltage, the MCSU-4 has the ability to suppress
the SMR output voltage to a value lower than the minimum battery voltage.
158-1872-01
Possible Cause
Output voltage low due to SMRs off
Float level set too low
Battery Disch level set too high
Comms cable faulty
SMR communication circuits faulty
Faulty MCSU-4
AC voltage out of tolerance
AC voltage threshold levels incorrect
Faulty AC monitoring unit MMIB1or2
MUIB or MCSU-4 faulty
Communications link failure
(Only on systems not fitted with AC
monitoring module)
AC frequency out of tolerance
AC frequency threshold levels incorrect
Faulty AC monitoring unit MMIB1 or 2
MUIB or MCSU-4 faulty
Battery charging current is being limited
to preset value
Battery current limit set too low
Battery current sensor faulty
Faulty MUIB or MCSU-4
One Battery string is faulty
Battery discharge current differential
level set too low
Battery current sensor is faulty
Faulty MUIB or MCSU
Excessive Earth current due to either
failure of load supply isolation or faulty
load equipment.
Action Suggested
Check AC voltage & restore if possible;
Set float level to correct value
Set correct Battery Disch level
Replace cable
Replace SMR
Replace MCSU-4
Check AC voltages and fix if possible
Set correct levels
Replace monitoring unit
Replace MCSU-4
In SMR menu check status of all SMRs.
If all show "No Response" check 4-way
communications cable between MCSU-4
and all SMRs
Check AC frequency and fix if possible
Set correct levels
Replace monitoring unit
Replace MCSU-4
No action necessary
Set correct limit
replace sensor
Replace MCSU-4
Repair/replace battery if necessary
Set correct level of Disch I Diff in BATT
menu
Check and replace sensor if necessary
Replace MCSU-4
Locate source of earth leakage current
and correct accordingly.
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Rectifier Technologies
19-Feb-14