Operation
45
Liebert
®
NXL
™
2.15.12 Load Transfer—1+N System: Transfer to Maintenance Bypass
Follow these instructions to manually transfer the load between Maintenance Bypass and the System
Static Bypass. Do not transfer the load between Maintenance Bypass and the System Inverter output.
Use the Monitor/Mimic Display screen to determine whether the UPS bypass line is available.
Load Transfer—1+N System: Transfer to Maintenance Bypass if Load is on System Static
Bypass
This section lists typical step-by-step instructions. The touchscreen will list all steps required for the
process, based on the unit’s condition and other factors.
1. Transfer the UPS system to bypass (see
2.15.10 - Load Transfer—1+N System: Transfer
). The “OK to transfer” lamp on the key-release unit will light.
2. If using a key interlock system, depress the key-release unit push button, turn the key and
remove it from key-release unit.
3. If using a key interlock system, insert the key into the lock for the Maintenance Bypass Breaker
(MBB); retract the bolt.
4. Close the Maintenance Bypass Breaker (MBB).
5. Open the Maintenance Isolation Breaker (MIB). The UPS system is now isolated from the critical
load and the load is now on Maintenance Bypass.
6. If using a key interlock system, remove the key from the lock for the Maintenance Isolation
Breaker (MIB).
7. If the maintenance bypass cabinet or switchboard has an optional, two-key interlock system,
reinsert the key into the solenoid.
8. If UPS bypass shutdown is required, open the Bypass Input Breaker (BIB).
Load Transfer—1+N System: Transfer to UPS if Load is on Maintenance Bypass
1. If the UPS modules are Off, start the system. Refer to
2. Place all the UPS units in the system on Static Bypass. Refer to
System: Transfer System to Bypass
3. If using a key interlock system, depress the key-release unit push button, turn the key and
remove from key-release unit.
4. If using a key interlock system, insert the key into the lock for the Maintenance Isolation Breaker
(MIB); retract the bolt.
5. Close the Maintenance Isolation Breaker (MIB).
6. Open the Maintenance Bypass Breaker (MBB). Load is now on UPS System Static Bypass.
7. If using a key interlock system, remove the key from the lock for the Maintenance Bypass Breaker
(MBB) to lock it open.
8. If the maintenance bypass cabinet or switchboard has an optional two-key interlock system,
reinsert the key into the solenoid.
The UPS system can now be transferred from bypass to UPS (see
System: Transfer System to Inverter
).
NOTE
If the maintenance bypass cabinet or switchboard has any other type of custom interlock, follow
the specific instructions for that interlock system to remove the key.
NOTE
The UPS system is now locked in bypass and cannot be transferred until the key is returned.
NOTE
Failure to close the Maintenance Bypass Breaker (MBB) will interrupt power to the load.
NOTE
Failure to close the Maintenance Isolation Breaker (MIB) will interrupt power to the load
Содержание Liebert NXL 250 kVA
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