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View and Download Emerson Liebert NX user manual online. 10-20, 400V, 50/60Hz, 3x1. Liebert NX UPS pdf manual download. Also for: Liebert nx series.
- Emerson Liebert Nx 10-30kva User Manual 2017
- Liebert Nx 20kva
- Emerson Liebert Tech Support
- Emerson Liebert Nx 10-30kva User Manual Pdf
- Emerson / Liebert NX Overview. This reliable, constant power protection has made Emerson / Liebert NX Series the most universally selected UPS to support 10-200kVA critical loads. With its wide range of UPS capacities and features, the Liebert NX.
- View and Download Emerson Liebert NX user manual online. 10-20, 400V, 50/60Hz, 3x1. Liebert NX UPS pdf manual download. Also for: Liebert nx series.
Page 67: Maintenance mode, Parallel redundancy mode (system expansion), Frequency converter mode, Caution, Warning
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Operation
59
Normal Mode
Operating in normal mode, the NX’s rectifier derives power from a utility AC source and supplies reg-
ulated DC power to the inverter, which regenerates precise AC power to supply the connected equip-
ment. The rectifier also uses the utility source power to charge the batteries.
Battery Mode
When utility AC power fails, the NX protects the critical load by instantaneously channeling battery
power to the inverter which continues supporting the critical load without interruption. When utility
power returns and is within acceptable limits, the NX automatically shifts back to Normal mode, with
the rectifier powering the critical load.
Bypass Mode
When the NX is in bypass mode, the load is directly supported by utility power and is without battery
backup protection.
The NX’s static transfer switch will shift the load from the inverter to bypass mode without an inter-
The NX’s static transfer switch will shift the load from the inverter to bypass mode without an inter-
ruption in AC power if the inverter is synchronous with the bypass and any of the following occurs:
• inverter fails
• inverter overload capacity is exceeded
• inverter is manually turned off by user
• inverter overload capacity is exceeded
• inverter is manually turned off by user
Maintenance Mode
For maintenance or repair, the NX may be operated in maintenance mode. To place the NX in mainte-
nance mode, the load must be transferred to bypass and the inverter must be turned off. When those
conditions are met, the rotary switch may be turned to MAINT and the UPS may be shut down, per-
mitting disconnecting the batteries for maintenance.
Parallel Redundancy Mode (System Expansion)
For higher capacity, higher reliability or both, the outputs of up to four UPS modules can be pro-
grammed for directly paralleling while a built-in parallel controller in each UPS ensures automatic
load sharing.
Frequency Converter Mode
The Liebert NX can be programmed into frequency converter mode for either 50Hz or 60Hz stable
output frequency. The input frequency may vary from 40Hz to 70Hz. In this mode, the static bypass
operation is disabled and the battery becomes optional, depending on any requirement to operate in
battery mode (stored energy mode).
NOTE
If the inverter is asynchronous with the bypass, the static switch will transfer the load from the
If the inverter is asynchronous with the bypass, the static switch will transfer the load from the
inverter to the bypass WITH interruption in AC power to the critical load. This interruption
Some documents have a more fluid structure with many internal links. Program to use for a user manual.
will be less than 15ms (in 50Hz), or less than 13.33ms (in 60Hz). This interruption time may be
altered by modifying the Output transfer interrupt time setting.
!
CAUTION
The internal maintenance bypass must not be used when the UPS system is in 1+N parallel.
!
WARNING
The UPS input and output must be protected with external overcurrent protection devices. In
maintenance mode, the input and output busbars remain energized.
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UPS Status Messages
98
Bypass Unable to Trace
This alarm is triggered by an inverter software routine when the amplitude or frequency of bypass
voltage is beyond the normal range.
The amplitude threshold is fixed for positive and negative 10% rating.
This alarm automatically resets once the bypass voltage goes normal.
1. First verify that the bypass voltage and frequency displayed on the panel is within the selected
range. Note here the rated voltage and frequency are specified by “Output voltage level” and
“Output frequency level” respectively.
2. If the displayed voltage is believed to be abnormal, then verify the bypass voltage and
frequency presented to the UPS. Check the external supply if it is found to be faulty.
Contact Liebert Global Services at 800-543-2378 for assistance.
Bypass Abnormal
This alarm is triggered by an inverter software routine when the amplitude or frequency of bypass
voltage exceeds the limit.
This alarm automatically resets once the bypass voltage goes normal.
First check if there are some relevant alarms such as “Bypass disconnect open”, “Bypass phase
reverse” and “Mains neutral lost”. If they appear, solve them first.
1. Then verify that the bypass voltage and frequency displayed on the panel is within the bypass
limit. Note here the rated voltage and frequency are specified by “Output voltage level” and
“Output frequency level” respectively.
2. If the displayed voltage is believed to be abnormal, then verify the bypass voltage and
frequency presented to the UPS. Check the external bypass supply if it is found to be faulty. If
the utility is likely to trigger this alarm frequently, the bypass limit can be changed a little larger
through the configuration software according to the customer’s agreement.
Contact Liebert Global Services at 800-543-2378 for assistance.
Inverter Asynchronous
This alarm is triggered by an inverter software routine when the inverter and bypass waveforms
are misaligned by more than 6 degrees in phase. This alarm resets automatically once the
condition is no longer true.
1. First check if the alarm “Bypass unable to trace” or “Bypass abnormal” occurs. If so, solve it
Emerson Liebert Nx 10-30kva User Manual 2017
first.
2. Verify the waveform of the bypass voltage. If it is too distorted, ask the customer to verify and
seek any possible measurements.
Contact Liebert Global Services at 800-543-2378 for assistance.
Inverter Fault
This alarm indicates a fault condition exists within the inverter.
Contact Liebert Global Services at 800-543-2378 for assistance.
Inv. Inductor Overtemp.
The temperature of the output filter inductor is too high to keep inverter running.
This alarm is triggered by the signal from a thermostat mounted in the output filter inductor.
The UPS would recover automatically after a 5 minute delay from the disappearance of the
overtemperature signal.
If the overtemperature condition is true then check for and verify:
1. high ambient air temperature.
2. blocked cooling airway.
3. any fan failure.
4. prolonged inverter overload.
Contact Liebert Global Services at 800-543-2378 for assistance.
Inverter Overtemp.
The temperature of the inverter heat sink is too high to keep inverter running.
This alarm is triggered by the signal from a temperature monitoring thermostat on the inverter
bridge heat sink.
The UPS will recover automatically after a 5 minute delay from the disappearance of the
overtemperature signal.
If the overtemperature condition is true, then check for and verify:
1. high ambient air temperature.
2. blocked cooling airway.
3. any fan failure.
4. prolonged inverter overload.
Contact Liebert Global Services at 800-543-2378 for assistance.
Fan Fault
Liebert Nx 20kva
At least one of the cooling fans fails. Contact Liebert Global Services at 800-543-2378 for
Emerson Liebert Tech Support
assistance.
Inverter STS Fail
At least one of the static switches of inverter side is open or short circuit. This fault is locked until
power off. Contact Liebert Global Services for assistance at 800-543-2378 for assistance.
Bypass STS Fail
At least one of the static switches of bypass side is open or short circuit. This fault is locked until
power off.
Contact Liebert Global Services at 800-543-2378 for assistance.
Table 44
UPS status messages (continued)
Emerson Liebert Nx 10-30kva User Manual Pdf
Event Message
Description / Suggested Action (if any)
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