Emerson Liebert NXL, Operation And Maintenance Manual

Page: 54 / 72

UPS Alarm and Status Messages
48
Byp Overload
Ph C
The critical load is greater than 110% while the
UPS is on bypass. The controls may shut the unit
down if the overload condition does not clear
within the allotted time. Allotted time is variable,
and is inversely proportional to the amplitude of
the overload, i.e., the greater the amplitude of the
overload, the less time the unit continues to
support the load.
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.
Press “SILENCE” to silence the audible alarm.
Observe the calculated load percentage on C phase
displayed on the Module Output Meter. If the
C phase steady state load percentage exceeds
110%, perform the following:
If Maintenance Bypass is available, follow Standard
Operating Procedures to transfer the load to
Maintenance Bypass.
If Maintenance Bypass is not available but the
system has an Internal Bypass Breaker (CB3 on the
One-Line Display), close CB3. Note that depending
on the severity of the overload, the possibility exists
that CB3 could trip if the overload exceeds the
breaker rating.
Investigate the overload condition.
If the Module Output Meter does not indicate an
overload condition, perform the previous steps and
contact your factory-authorized service provider.
Bypass Breaker
(CB3) Close Fail
The bypass circuit breaker has failed to respond
to a close signal.
Bypass Breaker
(CB3) Open Fail
The bypass circuit breaker has failed to respond
to an open signal.
Bypass Line Fail The bypass source is not present.
Bypass Not Avail
This summary event indicates a problem with the
detected bypass voltage. If bypass is not
available, transfers to bypass are disabled.
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.
Press “SILENCE” to silence the audible alarm.
Observe the One-Line Display. The bypass power
line feeding the static switch is green when bypass
power is within normal operating range. If the line
feeding the static switch is orange, gray, or black,
bypass voltage is out of tolerance. Also check the
bypass voltage readings on the Bypass Meter.
When the bypass returns to normal, this alarm
clears automatically. If all indications checked
above are normal and the alarm is still present,
contact your factory-authorized service provider.
If there is a problem indicated with the bypass
voltage, investigate and resolve the issue.
Examples of conditions that could cause this alarm:
Unstable generator voltage; or, Bypass Feeder
Breaker tripped.
Bypass OF/UF
The bypass frequency has exceeded the bypass
frequency limit of ± 5 Hz of nominal. If this alarm is
active, transfers to bypass are disabled.
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.
Press “SILENCE” to silence the audible alarm.
Check the frequency on the Bypass Meter. If the
frequency is outside the synchronization range,
investigate and resolve the issue.
This alarm is commonly the result of an uncalibrated
generator, or power anomalies on the utility feed.
Check bypass power for nominal limits.
If bypass frequency appears normal, contact your
factory-authorized service provider.
Controller Error
This is a summary event that indicates a DSP
communication error.
The Controller Error event is a fault condition that
indicates a loss of communications in the
controls.
Press “SILENCE” to silence the audible alarm.
Press “RESET” to attempt to reset the fault.
Contact your factory-authorized service provider.
Table 7 Liebert NXL alarm and status messages (continued)
Event Message Event Definition Recommended Action