75
User Manual 10H52258UM60 - Rev. 3 - 01/2019
Parallel System and LBS System
APM 400/600
•
Press the EPO button to stop the rectifier, static switch, and battery.
•
Disconnect the Rectifier input switch Q1, Bypass switch Q2, on each UPS. At this point, all the internal power
supplies are off and the LCD does not display any information.
•
Disconnect the output switch Q5 on each UPS.
Warning
•
Post a label at the AC input distribution point (normally located at a distance from the UPS) to notify
other personnel that the UPS maintenance is in process.
•
Wait for 10 minutes for the internal DC bus capacitor to discharge so that the UPS is completely de-energized.
Warning: hazardous battery voltage
Hazardous voltages may still be present on the battery terminals even after the UPS is completely de-energized.
8.3.5
Procedures For Complete UPS Shutdown While Maintaining Power To Load
The following procedures may be used to shut the UPS down completely while maintaining the power supply to
the load. Refer to the procedures in 8.3.2 Maintenance Bypass Procedures.
8.4
Installing the Cabinet
A LBS system consists of 2 independent UPS systems, each containing one or more parallel UPS modules as
illustrated in Figure 8-5.
The LBS system provides ultra-high reliability and is ideally suited to loads with multiple inputs. In the case of
single-input loads, they may be supplied via an STS unit.
The system uses the LBS cables to maintain the output of the two independent (or parallel) UPS systems in
synchronization. The system is based on a master-slave relationship, where one of the systems is the master
while the other is a slave. The parallel system operating modes consist of master and slave modes in normal or
bypass mode.
Place the UPS modules side by side and interconnect the UPS modules as illustrated in Figure 8-5.
Figure 8-5 LBS system
•
In Figure 8-5 above, switches Q1, Q2, and Q5 are optional, whereas Q3 is fitted as standard.
•
In a dual bus system, both the UPS systems must have the same voltage and frequency. The load should not
