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7.2.2 Parallel System shutdown with Load transfer on External Maintenance Bypass
(option)
NOTE !
Not following this procedure can cause protected loads to shut down!
Never close or open either UPS Output Switch Q1 and External Maintenance Bypass
Switch (option) with the Inverter running!
Initial situation: the Load is powered by all Inverters of the Parallel System.
If eBoost™ option is available, make sure that eBoost™ Operation Mode is disabled
before starting the shutdown procedure.
The complete UPS Parallel System has to be turned OFF, while providing the Load
power by Utility through a single External Maintenance Bypass (option).
With the UPS Parallel System in normal operation and the Inverters supplying the Load, the UPS Output
Switches Q1, Input Circuit Breakers CB4 and the Battery Bank Breakers are closed (Pos. I) and the
External Maintenance Bypass Switch (option) is open (Pos. O).
The Synoptic Diagram, on all UPS units, must display the
status "LOAD SUPPLIED BY INVERTER".
1.
Disconnect the Inverter by pressing the "Inverter OFF" ( O ) key on all Units, and hold until the
LED 5 (Inverter available) turns OFF
At no redundancy, the system will transfer to Utility supply.
LED 5 (Inverter available) is Off
LEDs Alarm are lit and the LEDs Operation are Off.
The Synoptic Diagram, on all UPS units, must display the
status "LOAD SUPPLIED BY AUTOMATIC BYPASS".
2.
Transfer the Load from Internal Automatic Bypass to External Maintenance Bypass (option).
Use the External Maintenance Bypass panel instructions to transfer the Load from the UPS to External
Maintenance Bypass Breaker (MBB).
After this step, the Load is supplied by the Utility through the UPS Automatic Bypass of all units and single
External Maintenance Bypass (option).
3.
Open the UPS Output Switch Q1 (Pos. O) on all UPS units.
The Load is now supplied only through the External Maintenance Bypass.
Modifications reserved
OPM_SGS_USM_M75_M75_2US_V010.doc
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User Manual SG Series 750 UL S2 & SG Series 750 T12 UL S2
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