Vertiv Liebert APM 300, User Manual

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56 Chapter 7 Parallel System And Dual Bus System
APM 300 Integrated UPS Single Module And Parallel System User Manual
7.3.2 Maintenance Bypass Procedures
Warning
If the UPS system is composed of more than 2 parallel UPS modules, and the load capacity exceeds the single module
capacity, do not use the internal maintenance bypass switch.
This operation will make the load transfer from UPS power supply protection state to direct connection with
AC input bypass state.
For the detailed operation procedures, see
5.3.4 Transfer From Normal Mode To Maintenance Mode .
7.3.3 Isolation Procedures (Of One UPS In A Parallel System)
Caution
The following procedures will switch off all power to the load.
The following procedures are used to isolate one UPS from a parallel system.
1. Press the EPO key of the UPS to be isolated.
2. Open the rectifier input switch, bypass input switch and BCB of the UPS.
At this point, other UPSs report 'Parallel Comm. Fail', which is normal. Other UPSs continue to power the load
through the inverter.
3. Open the output switch of the UPS.
4. Wait for 10 minutes before carrying out UPS maintenance or repair.
Warning: hazardous battery voltage
The UPS battery and connecting terminals remain energized at hazardous voltage levels at all times.
7.3.4 Insertion Procedures (Of One UPS In A Parallel System)
The procedures are used to re-integrate a UPS that has been previously isolated from a parallel system. It is
assumed that the installation is completed and the system has been commissioned by authorized personnel.
1. Close the output switch of the UPS to be re-integrated.
2. Close the rectifier input switch, bypass input switch and BCB of the UPS.
3. Press and hold the INVERTER ON key of the UPS for 2s.
The inverter starts up, and the inverter indicator starts flashing in green color. When the inverter is ready, the
UPS transfers to parallel operation with other UPSs, and the inverter indicator goes to a continuous on state.
The UPS is in normal mode, and the UPS indicator states are as listed in Table 7-1.
Table 7-1 UPS indicator state
Indicator State
Rectifier indicator Green
Battery indicator Off
Bypass indicator Off
Inverter indicator Green
Output indicator Green
Status indicator Green