Maintenance
Sageon II 200A (N+1) Power Distribution System
PM990-5202-200, Rev. 6
6-7
Symptom
Likely Causes
Action
One unit is alarmed as HVSD (high
voltage shutdown) and is latched off.
The unit has developed a fault that
causes it to output a voltage above the
HVSD protection limit and has been
supplying load current while above this
voltage limit.
A random event on the DC bus has
occurred that forced a unit into HVSD.
Replacing the rectifier module is
recommended. However, a random
event may have triggered the HVSD and
to determine if the unit has a real fault,
the HVSD latched alarm can be reset
using the “Reset Latched Alarm”
function in the controller rectifier menu.
(If the system does not have any
batteries, cycling the AC power will
have the same effect). If the unit does
not recover by latching off again, it is
faulty.
“Rectifier Urgent” alarm activated
One or many rectifiers are off due to AC
power failure, internal faults, incorrect
command signal from controller 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. 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
controller to reset the system.
A rectifier is indicating “Rectifier Off”
or “No Response” on the controller
rectifier display
CONTINUE: A rectifier is indicating
“Rectifier Off” or “No Response” on the
controller rectifier 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 “Rectifier Off” if
the AC has failed on its input. Once the
internal power dies, the unit will no
longer communicate and controller will
indicate “No Response”.
“No Response” all the time and the
rectifier 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 rectifier 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 controller 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
RECTIFIER” alarm
The controller has not been able to make
the unit share the load with the other
units. Either the rectifier 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
Controller cannot reach the desired
system voltage. This can be due to
possible excessive voltage drop along
the DC bus bars, inside one or more
rectifiers or “System V Drop” parameter
has been set too low.
Increase “Sys V Drop” parameter.
Replace faulty rectifier (unlikely to
current share as well).
Check that the number of rectifiers in the
system is correctly set (more rectifiers
than declared can generate this problem).