Liebert UPS System user manual Shutdown maintenance

Chapter 6 Maintenance

system will not start battery self test if the last self-test interval satisfies the “battery discharging interval”, but does not satisfy the manual self test condition, and the system will wait until the conditions are satisfied.

6.2.3 Shutdown maintenance

For large capacity UPS, periodical checking is required to ensure the normal operation and proper condition. Notify us if any fault is found. In order to maintain the uninterrupted power supply to the load, please shut down the UPS according to the following procedures:

1.Press the “inverter shutdown” button to shut down the inverter, the system transfers to bypass mode;

2.Switch off Q1 and QF1 one by one;

3.Switch on the maintenance bypass switch Q3BP;

4.Switch off the Q2 and Q5 one by one.

5.Now, the load is powered by the maintenance bypass of UPS. Conduct maintenance or checking to the UPS after waiting for 8 minutes and the DC bus capacitor discharges to zero voltage.

If the UPS is required to be shutdown totally, switch on the external maintenance bypass switch KBP after switch off the Q2 and Q5; then switch off the Q3BP, thus the load can be powered by the maintenance bypass with interruption, and the UPS units replacement and capacity expansion can be done after switching off the input and output power distribution switches.

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