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VII. FAULTS AND TROUBLESHOOTING
7.1 General procedure for fault checking and troubleshooting
UPS contains complicated electronic control circuits. In order to locate any fault occurring circuits, an ad-
vanced knowledge about the circuitry and its operation principles must be known. The aim of this section is to
give the knowledge required at the first intervention.
There is no practical way to locate any possible fault. Most of the faults do not occur as a performance dec-
rement. Generally, the UPS operates normally or switches into by-pass mode. But in order to determine any
change in load or the system the parameters must be recorded regularly as mentioned previously.
Generally, the output voltage can deviate %2 from the predefined values. If values differ more than this per-
centage then reasons must be investigated.
The following general structure must be systematically followed while trying to indicate the error:
Fault determination:
First step is to record the messages, indicator panel LEDs, operating parameter
values and last status of switches. This must be done before attempting to press
any button.
Fixing interventions:
After recording all indications, check the meaning of the fault and alarm messages
using “The operator control indicator panel”. If anything related, follow the related
procedure.
Reporting the fault:
Service personal must clearly report the work done. Hence, if any other error oc-
curs there will be enough information to fix it.
