02/02
62
6.1 Troubleshooting UPS Systems
The UPS contains complex electronic control circuits that require a
firm understanding in order to carry out comprehensive fault
diagnosis and repair of the equipment. The following information
aims to provide a trained user with sufficient knowledge to understand
the nature of a fault through the correct interpretation of the
accompanying alarms and indications, and to carry out any necessary
first aid repair action.
WARNING
Some of the Instructions in the charts at the end of this
chapter involve checking internal fuses. This should be
undertaken (after the equipment has been shut down) only
by a trained electrician who is familiar with the layout and
operation of the equipment and fully conversant with the
areas of potential hazard.
Most UPS problems do not emerge as a gradual
performance degradation; generally the UPS either works correctly or
it will shut down - and transfer the load to the Bypass supply if
applicable. However, it is important to maintain a regular record of
the UPS meter indications, as suggested in the maintenance
instructions, in order that any change in the system or load
characteristics are readily identified.
In general, the output voltage should be within 2% of nominal. If the
UPS has not operated on battery power within the previous ten hours
the battery charge current should be typically less than 6A.
If any indication differs significantly from the typical figure given
above the cause should be investigated.
Information concerning prevailing load conditions can prove useful
when discussing problems with the service agent - for example, details
of any particular load being started or shed at the time the fault
occurred.
Troubleshooting should be carried out methodically using the
following guidelines:-
Fault Identification
When first summoned to the scene of a UPS fault, your immediate
action should be to observe and record the displayed messages,
mimic indications and the position of the UPS power isolator switches.
This should be completed before you touch any switch.
6.1.2
General
Troubleshooting
Procedure
Chapter 6 -Troubleshooting
6.1.1 Operating Parameters
& Limitations
