RT9 Powershelf
Rectifier Technologies
158-1806-01.doc
36
2-Mar-06
Symptom Likely
Causes Action
“SMR Urgent” alarm activated
One or many SMRs are off due to AC
power failure, internal faults, incorrect
command signal from MiniCSU-3 or all
rectifiers are in current limit
Check the AC power and restore.
Replace faulty rectifier modules.
Check for DC bus overload faults.
All units are latched off as HVSD
Absolute Overvoltage shutdown protection
activated. The system is likely to have no
load and without a battery. An event on
the DC bus has caused the voltage to
exceed 70V for 48V systems or 35V for
24V systems. The event could be caused
either by a faulty rectifier or other
equipment connected to the bus.
Add a small amount of load (>2A per
rectifier) to the system and check for a
faulty rectifier.
Check for other faulty equipment
connected to the bus that could cause the
overvoltage transient.
Use the “Reset Latched Alarm” from the
MiniCSU-3 to reset the system.
A rectifier is indicating “SMR Off” or “No
Response” on the MiniCSU-3 SMR display
An AC failure to the rectifier is the most
likely cause. While the rectifier internal
power rails are still available, the unit will
communicate with “SMR Off” if the AC has
failed on its input. Once the internal power
dies, the unit will no longer communicate
and MiniCSU-3 will indicate “No Response”
“No Response” all the time and the SMR is
known to have AC power indicates a
communications wiring problem.
Check the AC feed to the rectifier for a
tripped circuit breaker, blown fuse or faulty
connection.
Check the SMR communications 10-way
ribbon cable for broken connections and
replace cable if necessary.
One or more rectifiers has a current limit or
power limit alarm activated
Total load, including battery charging
current is equal to the output limits of the
rectifiers. (System overload)
One rectifier in current limit only indicates a
likely calibration problem with the module.
The MiniCSU-3 can usually compensate
for an out of calibration unit in a system
and will take a few minutes to adjust the
unit to correctly share the load.
Revise the load level on the system and
expand the number of rectifiers as required
to remove the overload condition.
One rectifier has an “UNCAL SMR” alarm
The MiniCSU-3 has not been able to make
the unit share the load with the other units.
Either the SMR is faulty (excessive internal
voltage drop) and cannot be adjusted to
share load, or it is too far out of calibration.
Replace the rectifier module. Send the unit
for repair and re-calibration.
“System Voltage Clamp” alarm activated
MiniCSU-3 cannot reach the desired
system voltage. This can be due to
possible excessive voltage drop along the
DC busbars, inside one or more rectifiers
or “System V Drop” parameter has been
set too low.
If this alarm comes up during equalise, the
maximum output voltage from the rectifier
may not be high enough to overcome the
system drops to the sense point and allow
the system to regulate at the desired high
equalise voltage.
Increase “Sys V Drop” parameter.
Replace faulty rectifier (unlikely to current
share as well).
Check that the number of SMRs in the
system is correctly set (more SMRs than
declared can generate this problem).
Revise the requirements for high equalise
voltage level.
SMR “EEPROM Fail” alarm is activated as
indicated at the SMR Menu for a particular
SMR.
Corrupted data found on the EEPROM
inside the rectifier that is outside the
allowable data range. The rectifier
software has attempted to over-write and
has failed due to the memory cell being
damaged.
Note, excessive electrical noise can
corrupt the read data transfer, which can
lead to the same alarm being generated.
Replace the faulty rectifier if the memory
cell is confirmed to have failed. This can
be done by, modifying each of the SMR
parameters on the MiniCSU-3 and
checking to see if the alarm clears.
(EEPROM corrects the data).
Check for EMC problems and
remove/reduce the source of electrical
interference where possible.
“EEPROM Fail” alarm for the MiniCSU-3 is
activated.
Corrupted data found on the backplane
EEPROM that is outside the allowable data
range. (similar to SMR corruption above)
Replace the faulty backplane if the memory
cell is confirmed to have failed.
“Range SMR” alarm for the rectifier is
activated.
Corrupted data found on the EEPROM
inside the rectifier that is inside the
allowable data range but does not match
the value programmed.
Try adjusting the SMR parameters to se if
the EEPROM cells can be updated. If not,
replace the faulty rectifier.
