Thomas & Betts 9395 - Manual (Page 60)

UPS 225 - 275 kVA
User’s and Installation Guide
1027212
Revision B
0
5.3.5 Transfer from bypass to normal mode
To transfer the critical load to Normal mode, perform the following procedure:
1. Press the CONTROLS pushbutton on the main menu bar. The System Controls screen
appears.
2. Press the NORMAL pushbutton on the System Controls menu bar. The UPS transfers to
Normal mode. If the power processor is not available, the system remains on bypass and
an alarm sounds.
3. The UPS is now operating in Normal mode, and the NORMAL status indicator is
illuminated. The power module (PM) status indicates ONLINE.
5.3.6 Transfer from normal to bypass mode and shut down UPS
To transfer the critical load to Bypass mode and shut down the UPS, perform the following
procedure:
1. Transfer the critical load to bypass by performing the procedure in paragraph 6.3.4.
2. Press the CONTROLS pushbutton on the main menu bar. The System Control screen
appears.
3. Press the pushbutton to display System Controls Screen 2.
4. Press the PM OFF pushbutton on the System Controls menu bar.
The power module (PM) status indicates SHUTDOWN. The input and output contactors open,
the battery breaker or disconnect is tripped, and the power module is turned off. The bypass
source supplies the critical load.
WARNING
Power is present inside the UPS cabinets.
5.3.7 UPS and critical load shutdown
To perform maintenance or service on the critical load, shut down power to the load by
performing the following procedure:
1. Turn off all equipment that is being powered by the UPS.
2. Perform the LOAD OFF procedure in paragraph 5.3.9. The input, output, and bypass
backfeed contactors open, the battery breaker or disconnect is tripped, and the power
module is turned off.
WARNING
Power is present inside the UPS cabinet until the upstream input feeder circuit breaker is
opened.
3. If the UPS contains input breaker CB1, open the UPS input breaker CB1.
4. Open the UPS input and bypass feeder circuit breakers.