Emerson Liebert NXL series Operation And Maintenance Manual page 85

Liebert NXL UPS
Event Message Event Definition
Inverter Fault
This summary event indicates a
potentially serious problem in the
Inverter.
The controls react to an Inverter fault in
different ways depending on the root
event that caused the fault. If bypass is
available, the controls transfer to static
bypass.
A restart may or may not be possible
ISS SCR Shorted
The controls have detected voltage on
the Inverter (Line side) side of the
Inverter Static Switch.
This indicates that an SCR is shorted.
With the Output SCRs turned off, there
should be no voltage present inside the
UPS.
This is a non-recoverable fault, and
inhibits normal start up of the UPS.
LBS Inhibited
With LBS operation enabled, conditions
required to allow LBS operation are not
met.
Voltage or Frequency differences sensed
by the LBS control are preventing the
ability of LBS to function correctly.
This alarm is self-clearing. When the
condition is no longer present, the alarm
and any control activity tied to the
alarm reverts to normal.
LBS Operating
Load Bus Synchronization (LBS) is
enabled and is active.
This status message informs the user
that one system in an LBS system has
lost its synchronization source (usually
its own Bypass) and is now
synchronized to the other system by the
LBS controls.
This status message is self-clearing.
When the condition is no longer present,
the alarm and any control activity tied
to the alarm reverts to normal.
Liebert NXL alarm and status messages (continued)
Page 85
Operation and Maintenance Manual 250-300-400-800kVA
Recommended Action
Press "SILENCE" to silence the audible
alarm.
Check the One-Line Display to determine
the state of the UPS. If both the Rectifier
and Inverter are
shut off, press "RESET" to attempt to
clear any latched alarms or faults.
Attempt a restart by pressing "Startup,"
"Manual Start," and follow the prompts to
place the UPS back in service.
If the startup fails, contact your factory-
authorized service provider.
If the Rectifier and Inverter appear to be
running, press "RESET" to attempt to
clear any latched alarms or faults, then
attempt a transfer by pressing "Transfer,"
"UPS." If the transfer is successful,
contact your factory-authorized service
provider.
If the transfer is unsuccessful, contact
your factory-authorized service provider.
Press "SILENCE" to silence the audible
alarm.
Turn off Control Power to clear the event.
Wait 5 minutes before re-applying
Control Power.
If the fault fails to clear, contact your
factory-authorized service representative.
Press "SILENCE" to silence the audible
alarm.
Check both Systems and verify normal
operation:
a. Both Systems running online on
inverter; b. Neither System in
Maintenance Bypass; c. No Bypass,
Input, or Synchronization errors present
on either system. If the cause of the
alarm cannot be determined by checking
both Systems, contact your factory-
authorized service provider.
Under normal circumstances, none. If
this message is active, and there is no
clear reason why the LBS circuit should
be active, contact your factory-authorized
service provider.