UPS OPERATING INSTRUCTIONSEaton®9390 UPS (20–80 kVA) and 9390IT (20-40 kVA) Installation and Operation Manual 164201603 Rev 4 www.eaton.com/powerquality9-129.2 Multiple Module Parallel Operation9.2.1 Starting the Parallel System in Normal ModeNOTE When starting a 9390IT UPS with internal batteries, remove the battery compartment access panelby loosening the wing nut at the bottom of the panel and lifting the panel off the retaining hook at the top.(See Drawing 164201603-12 on page A-67)To start the parallel system:1. Close all uninterruptible power module (UPM) input feeder circuit breakers.2. If the UPMs are dual feed, close all UPM Bypass input feeder circuit breakers.3. Observe all UPM control panel displays becoming active, indicating logic power.4. Press the CONTROLS pushbutton on the main menu bar of any UPM. The SystemControls screen appears on each UPM.5. On the System Controls screen of each UPM, the power module (PM) statusshould indicate SHUTDOWN.6. Press the NORMAL pushbutton on the System Controls menu bar of any UPM.If Auto Bypass is enabled, the critical load is immediately supplied by the bypasssource, in Bypass mode, until the inverters turn on and the UPMs transfer toNormal mode. The status indicator on each UPM control panel indicates the UPMis in Bypass mode. If Auto Bypass is not enabled, the UPM outputs remain offuntil the UPMs transfer to Normal mode.7. Observe the following messages appear sequentially on the power module (PM)status line of each UPM:DC STARTINGINVERTER STARTINGINVERTER SYNCINGREADYONLINEThe rectifier and inverter turn on. The inverter continues to ramp up to fullvoltage.8. Close the battery breakers for each UPM any time after INVERTER SYNCING orCLOSE BATTERY appears on the display.Once the inverter reaches full voltage, and the battery breaker is closed, eachUPM output contactor K3 closes and each static switch turns off. Power is nowsupplied to the critical load in Normal mode. It takes approximately 1 minute forthe UPMs to achieve Normal mode.9. The UPMs are now operating in Normal mode and the NORMAL status indicatoron each UPM is illuminated.10. Reinstall the battery compartment access panel.