User Manual 10H52258UM60 - Rev. 3 - 01/2019
74
APM 400/600
Parallel System and LBS System
7. Open the rectifier input switch Q1, bypass input switch Q2 and external battery breakers or fuses on each UPS
in turn.
At this point, all the internal power supplies are off and the LCD does not display any information.
Warning
1. If it is necessary to carry out maintenance work, wait for 10 minutes for the internal DC bus capacitor to discharge.
2. Hazardous voltages may still be present on parts of the UPS circuit even after the rectifier input switch, bypass
input switch and battery switch have been opened. Therefore, UPS maintenance operations should be carried out by
qualified personnel only.
8.3.3
Procedures For Isolating One UPS Module From a Parallel System
Important
These procedures may only be carried out by Vertiv service personnel or under their guidance.
Warning
Before carrying out this operation, confirm that the system has sufficient redundancy capacity to avoid system
shutdown due to overload.
The following procedures apply when one UPS module must be isolated from the parallel system for repair due to
a serious fault:
1. Pressing the EPO button switches the rectifier, inverter, static switch and battery off, but does not affect other
the UPS modules in the parallel system, which will continue to supply the load as normal.
2. Set 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 to the OFF position.
3. Connect the remaining parallel cables correctly to the other modules, refer to 8.2.5 Parallel Cables.
Warning
1. 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.
2. Wait for 10 minutes for the internal DC bus capacitor to discharge so that the UPS is completely de-energized.
8.3.4
Procedures For Re-inserting a UPS Module Into a Parallel System
Important
These procedures may only be carried out by Vertiv service personnel or under their guidance.
The following procedures are used to reintegrate a UPS module into a parallel system that it was removed from
previously:
1. Confirm that the I/O, battery and parallel cables are connected correctly to the module to be re-inserted.
2. Confirm that the maintenance bypass switch Q3 or the single module external maintenance switch is in the
OFF position. 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 on each UPS in turn.
3. When the single module rectifier indicator assumes the steady, green state, close the BCB and then press the
INVERTER ON key.
At this point, the inverter indicator on the module being inserted starts to flash green. A few seconds later, the
module is reintegrated into the parallel system.
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Procedure for shutting down the UPS completely
The following section defines the step-by-step procedures for shutting down the UPS and the load. All the
isolating switches and breakers are opened and the UPS no longer supplies power to the load.
Caution
The following procedures will interrupt the power supply to the load, completely de-energizing it.
