Chapter 6 Operating Instructions 45
NXr UPS Module And Parallel System 30kVA ~ 200kVA User Manual
maintain the UPS.
Caution
When the UPS is in maintenance mode, the load is not protected against abnormal mains supply.
6.4 Procedures For Completely Powering Down The UPS
Caution
The following procedures will switch off all power to the load.
Warning: hazardous battery voltage
The UPS battery and connecting terminals remain energized at hazardous voltage levels at all times.
The following procedures are used to completely power down the UPS and load. All power switches, isolators and
circuit breakers will be opened and the power will be removed from the load. In a parallel system, perform each step
of the procedures in every UPS module before proceeding to the next step.
1. Press the EPO switch on the UPS front panel. This disables the rectifier, inverter, static transfer switch and battery
operation, and the load is de-energised.
Note: Unless in an emergency situation, do not press the remote EPO switch.
2. Open the external a.c. input switch and BCB. In split bypass configuration, it is required to open both a,c. input
switches.
In a parallel system, at this point, other UPSs report Parallel Comm. Fail, which is normal. Other UPSs continue to
power the load through the inverter.
All of the indicators and the LCD on the front panel will extinguish as the mains-driven internal power supplies decay.
3. Open the external a.c. output switch of the UPS.
6.5 Procedures For Completely Powering Down The UPS While Maintaining he
Power Supply To The Load
Caution
Ensure that the UPS has been installed with an external maintenance bypass cabinet before carring out these procedures.
The following procedures are applicable for completely powering down the UPS and still keeping the power supply to
the load. In a parallel system, perform each step of the procedures in every UPS module before proceeding to the
next step.
1. Use the procedures in
6.3.4 Transfer From Normal Mode To Maintenance Mode
to transfer the UPS to
maintenance mode.
2. Close the maintenance switch of the external maintenance bypass cabinet.
3. Open the external a.c. input switch of the UPS. In split bypass configuration, it is required to open both external a.c.
input switches.
4. Open the output switch of the UPS.
6.6 Isolation Procedures (Of One UPS In A Parallel System)
Caution
The following procedures will switch off all power to the load.
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