Modifications reserved
Page 49/71
OPM_SGS_USM_M75_M75_2US_V010.doc
User Manual
SG Series 750 UL S2 & SG Series 750 T12 UL S2
7.1.2 UPS 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 the
Inverter
.
If
eBoost™
option is available, make sure that
eBoost™ Operation Mode
is
disabled before starting this procedure.
The complete UPS system has to be turned OFF, while providing the
Load
power
by
Utility
through the
External Maintenance Bypass
(option).
With the UPS in normal operation and the
Inverter
supplying the
Load
, the
UPS Output Switch Q1
and
the
Input Circuit Breaker CB4
are closed (Pos. I)
.
External Maintenance Bypass Switch
(option)
is open
and the
Battery Circuit Breaker
is closed (Pos. I)
.
The
Synoptic Diagram
must display the status
“
LOAD
SUPPLIED BY INVERTER
”
.
1. Disconnect the Inverter by pressing the
“
Inverter OFF
”
( O ) key and hold until the LED 5
(Inverter available) turns OFF.
The
Load
is transferred to
Utility
by
Automatic Bypass
.
Inverter
shuts down.
LED 5 (Inverter available)
must be OFF.
LED Alarm
is lit and the
LED Operation
is Off.
The
Synoptic Diagram
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 Automatic
Bypass
to
External Maintenance Bypass Breaker (MBB)
.
After this step, the
Load
is supplied by the
Utility
through the
UPS Automatic Bypass
and the
External
Maintenance Bypass (option)
.
3. Open the UPS Output Switch Q1 (Pos. O) and then press the “Load Off” key.
The
Load
is now supplied only through the
External Maintenance Bypass (option)
.
Rectifier
shuts down and all input and output
contactors
are opened.
Press the
“MUTE”
key to reset the
alarm buzzer
.
4. Disconnect the battery by opening the Battery Circuit Breaker.
Wait
5 minutes
for DC-Link Capacitors discharge.
The
Load
is now powered from the
Utility
through
External Maintenance Bypass (option)
.
END OF PROCEDURE
WARNING!
It will take a minimum of 5 minutes for the DC capacitors to discharge.
Open only the front door, do not open any other part of the UPS.