7.4.9
Shutting down the UPS system and critical load
To do maintenance or service on the critical load, shut down the power to the load
by performing the following procedure:
1.
Turn off all the equipment that is powered by the UPS system.
2.
Do the LOAD OFF procedure (see
Section 7.4.10 De-energizing the critical
).
The input, output, and bypass backfeed contactors open, the battery breaker
or disconnect is tripped, and the power module is turned off.
3.
Open the UPS front door.
4.
Open the rectifier input switches.
5.
Make sure that the battery breaker is open.
6.
Close the UPS front door.
7.
Open the UPS input and bypass feeder circuit breakers.
8.
Repeat steps 3–7 for all the UPSs in the system.
DANGER
Power is still present inside each UPS cabinet until the upstream feeder
circuit breaker is opened, and in case of a parallel system, the output is
isolated or parallel units are shut down as well.
7.4.10
De-energizing the critical load
Initiate a UPS system Load Off by pressing the
Load Off
button in the
Controls→System Controls
screen. This button can be pressed to control the
UPS output. The
Load Off
button de-energizes the critical load and shuts down
the UPS system. The UPS system (including bypass) remains off until it is
restarted.
1.
Press
Load Off
.
The shutdown screen appears, providing a choice to proceed or abort the
shutdown.
2.
To shut down the UPS, press
Load Off
. To abort the shutdown, press
Abort
.
NOTE: All power to the critical load is lost when Load Off is selected. Only use
this feature when you want to de-energize the critical load.
When Load Off is selected, the input, output, and bypass backfeed contactors
open, the battery breaker CB1 or disconnect is tripped, and all the UPSs in the
system are turned off.
To restart the UPS system, follow the procedure in
Section 7.4.1 Starting the UPS
system in the double conversion mode
or
Section 7.4.2 Start the UPS system in
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Document ID: P-164000493
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Eaton 91PS/93PS UPS 8–40 kW
User’s and Installation Guide