Vertiv Liebert APM Plus - Procedures for Inserting One Isolated UPS Module in Parallel System

W ARN ING ! A fter isolating one U P S m od ule, w hen the parallel system is not overload, then
proceed w ith steps below .
The following procedures apply when one UPS module must be isolated from the parallel system for repair due to serious
fault:
1. Pressing the EPO button on the GHMI stops the operation of rectifier, inverter, static switch and battery, but this
action will not affect other UPSs in parallel system to power the load normally.
2. Disconnect the external power mains switch, rectifier input switch Q1, external power bypass switch, bypass
input switch Q2, output switch Q5, BCB and single module external output switch.
W ARN ING ! P ost a label at the AC inp ut distribution (generally far aw ay from the UPS) to alert
that th e U PS is und er m aintenan ce.
W ARN ING ! W ait 10 m inutes for the internal DC bu s capacitance d ischarging. T hen the UPS is
com pletely shut dow n.
8.3.4 Procedures for Inserting One Isolated UPS module in Parallel System
IM PO R T A N T ! These pro cedures shall on ly be carried ou t by service p ersonnel of Vertiv or und er
their guidan ce.
The following procedures are used to reintegrate a UPS module that has been previously isolated from the parallel system:
1. Confirm that the I/O cable, battery cable, and parallel cable of the single module are correctly connected.
2. Confirm that the maintenance bypass switch Q3 or the single module external maintenance switch is
disconnected. Close the output switch Q5, external output switch, external power bypass switch, bypass input
switch Q2, rectifier input switch Q1, and external power mains switch of each UPS in turn.
3. When the single module starts, close the BCB and then manually turn on the inverter.
Wait a few seconds after starting the inverter of inserted UPS system, it connects with existing systems for parallel operation
automatically.
8 Parallel System and LBS System
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Vertiv™ Liebert® APM Plus User Manual