Liebert UPS System - Manual (Page 76)

Chapter 6 Maintenance
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6.1.2 Shutdown
1. Shutdown in normal mode
When the UPS requires periodical checking or needs to stop operation, the
shutdown process in normal mode is given below:
1.Press the “inverter shutdown” button on the UPS panel for longer than two
seconds, shutdown the inverter and the system transfers to bypass mode.
2.Switch off the Q1 and QF1 one by one;
At this time the load is powered by bypass. If the load needs not to be powered,
then switch off Q2 and Q5 directly; If the load needs to be powered continuously,
the UPS should be shutdown for maintenance, follow the steps below:
3.Switch on the internal maintenance bypass switch Q3BP;
4.Switch off Q2 and Q5 one by one;
Now the load is powered by the maintenance bypass. Don’t conduct repairing and
maintenance work after waiting for 8 minutes until the voltage of DC bus capacitor
become zero due to discharging.
5.External maintenance bypass KBP should be installed if the UPS needs to be
shutdown totally. Switch off Q2 and Q5, close the KBP, and then switch off the
internal maintenance bypass Q3B, the load will transfer to external maintenance
bypass power without interruption. After this, the UPS unit replacement or capacity
expansion can be done after switching off UPS input and output switches.
2. Shutdown in bypass mode
Follow from step 2 to step 5 of the above “shutdown in normal mode” to shut down
the UPS in bypass mode.
3. Shutdown in battery mode
Note: when the bypass power is abnormal, shut down the UPS in battery mode will
result in the power interruption to the load.
Because the utility is not available, in order to shut down the UPS that is in battery
mode, switch off all the switches to realize shutdown in bypass mode after finishing
the first step in “shutdown in normal mode” .
4. Shutdown in ECO mode
The procedures of shutdown in ECO mode are the same with those of shutdown in
bypass mode.