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Chapter 11 – '1+N System'
11.2.4
Procedure for Switching the UPS system into a Maintenance Bypass condition from normal operation
- 1 + N Configuration (> two UPS's) or two UPS's with parallel power connection
1 + N Configuration (> 2 UPS's) or two UPS's with parallel power connection
It is advisable to take all the necessary measures to prevent the manual Bypass switch inside the UPS (Q3) from being
used. This can be done, for example, by removing the handle of the switch and placing on it a warning label for
maintenance personnel.
The first part of this procedure explains in detail how to disable the inverters and how to transfer the load to the
external maintenance Bypass by means of the UPS static switches. This procedure must be followed to transfer the
load from the UPS outputs to the maintenance bypass system, as required during UPS maintenance procedures.
The procedure can only be performed after the installation has been completed (which includes also the
maintenance bypass cabinet), after the system has been placed in operation by authorized personnel and after the
external power switches have been closed. See the reference drawing of Figure 4-8 for more information.
Note: the procedure can be performed only if option Castell Interlock has been correctly installed. If the system is
not equipped with this option, skip the points that describe the operations related to Castell keys (i.e. points 4-5-8).
The following window allows the operator to select the UPS inverter ON or OFF.
Before making this operation, read messages on display to be sure that bypass supply is regular and the inverter
is synchronous with it, not to risk a short interruption in powering the load.
IF YOU ARE NOT SURE OF WHAT YOU ARE DOING - THEN DO NOT DO IT.
1. Press the INV switch on the left side of the operator control panel.
2. Confirm this operation as instructed at the display:
WARNING! STOP
INVERTER REQUESTED
ENTER
TO CONTINUE
ESC
TO CANCEL
3. If Enter is pressed:
The Module Mimic indicator Load on Inverter ( 5 )will extinguish and the Load on Bypass indicator ( 6 ) will
flash amber, and also the red led (13) will flash and normally will accompanied by an audible alarm.
Pressing the Alarm Silence Switch cancels the audible alarm but leaves the warning message displayed until the
appropriate condition is rectified.
4. Rotate and remove the Castell key from the UPS module. The key, which is fixed in position by means of a
mechanical device, can only be removed by pressing the energising button of the solenoid and when the green
indicator is on.
5. Place and rotate the key in the Key Exchange Box located on or near the external Maintenance Bypass isolator
Panel.
6. Repeat steps 1÷5 for the other UPS modules.
Depending on the UPS system setup, when the number of modules available is less than the number needed in the
setup, all the remaining UPS modules will transfer the load to their Static Bypass.
7. The UPS inverter will now shut down and the load will transfer to the Bypass supply.
The Module Mimic indicator Load on Bypass (6) will flash amber and the Load on Inverter (5) indicator will
extinguish.
Page 11-8
Liebert Hipulse E
IMPORTANT
Press Enter for 1 second to confirm INV OFF
Press Esc for 1 second to exit
Your load is now powered via the Static Bypass system.
(07/04)
Caution
User Manual
Single or '1+N' UPS System
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