Powerware 9305 - Maintenance

7.5 kVA - 15 kVA UPS
Parallel for Redundancy System
User’s and Installation Manual
1012833
Revision 4
25
WARNING!
If the input voltage or frequency is not correct and the UPS system is not
synchronised to mains, the use of the maintenance bypass switch will cause a
break in the output voltage.
Going to bypass mode
If the maintenance bypass switch needs to be used, it is recommended to check that the
bypass input power is connected and present in the parallel module.
 Check that at least in one UPS the LINE ON LED is lit.
 Turn the maintenance bypass switch to BYPASS position.
Returning the normal mode
 Start up both UPSes according to the section 8.1 of this manual.
 Check that UPS ON and BYPASSED LEDs are lit in the front panel of UPSes
 Turn the maintenance bypass switch to UPS position.
9. Maintenance
Maintenance of a UPS units must be performed only by a person who has completed the
UPS service training.
9.1 Using the parallel module switches
Even though the parallel module includes some switches, these are to be used only by
service personnel from the manufacturer or from an agent authorised by the manufacturer.
The parallel module includes a maintenance bypass switch S3 (make before break type
switch) and two maintenance switches S1 and S2 for disconnecting the UPS outputs
during maintenance or service. See fig 11.
In the parallel for redundancy system one UPS can supply full load while the other UPS is
serviced. It is not necessary to use the maintenance bypass switch.
When one UPS needs maintenance or service the procedure is the following:
 shut down the UPS that needs maintenance or service
 disconnect the same UPS output with maintenance switch S1 or S2 depending on
which UPS has been turned off. If UPS1 needs service use maintenance switch S1
and if UPS2 needs service use maintenance switch S2.
When the UPS has been serviced and tested to be in order shut down the serviced UPS.
Turn the maintenance switch of the serviced unit back to ON position and start up the UPS
according instructions in section 8.1 in this manual.
When the UPS has been serviced and tested, turn the respective maintenance switch in
the parallel module back to ON position and start up the UPS according to the instructions
in section 8.1 in this manual.
Note
If it needed to transfer the load to bypass mode or return it to normal operation
mode, see section 8.4 of this manual.