Service manual

Always On UPS Systems
M0704_NX_Series_Service_Manual V2.17 2012-06-12 17
- Rectifier will ramp up its DC output voltage over a period of 20 seconds
and assume the load from the battery bank. It will then provide charging
current to the batteries.
- Indicators will show normal rectifier and inverter operation of the system.
Record UPS status
o Out of service, bypass mode
o Status form
12. UPS SHUTDOWN PROCEDURES
12.1. Complete UPS shut down procedure
a. Switch off the inverter – The inverter can be switched off by simultaneously
pressing the inverter off switch (O) and the inverter control switch (
◄►).
The load will be automatically transferred to reserve without interruption.
b. Open the battery fuse holder and or breaker – This will disconnect the
batteries from the DC bus and the UPS no longer has back up available.
This fuse holder or breaker can be located within the UPS system or within
the battery cabinets.
c. Open the rectifier breaker – Opening the rectifier breaker will remove the
power source from the DC bus. The DC bus will start to drop slowly until it
reaches a save level of approximately 20VDC.
WARNING!
Completing the next step will turn off the power to the loads.
Make sure all loads have been turned off before proceeding.
d. Open the Reserve breaker – Before opening the reserve breaker you must
make sure there is no critical load connected to the UPS that requires
power. NO OUTPUT POWER WILL BE SUPPLIED FROM THE UPS ONCE
THE RESERVE (UTILITY) BREAKER IS OPENED.
e. Open the Input breaker – transformers will de-energized.
f. Now that all power has been cut off within the UPS system. All LED’s,
displays and fans should be off.
12.2. From Inverter To Manual Bypass Procedure
The following procedures will allow the service personnel to switch the UPS
system to manual or maintenance bypass mode without interrupting the output
power to the loads.
a. Switch off the Inverter – The inverter can be switched off by simultaneously
pressing the inverter off switch (O) and the inverter control switch (
◄►).
The load will be automatically transferred to reserve (utility) supply without
interruption.
b. Open the battery fuse holder and or breaker– This will disconnect the
batteries from the DC bus and the UPS no longer has back up available.