Nature of Fault
Probable Reason
Action to be taken
Unit does not turn
ON.
•Input auxiliary supply
not coming.
•Input side fuse
(external)blown
•Check the input supply
& restore.
•Check input side fuses
(external) OK.
Unit does not turn
ON any capacitors
even if PF is below
Lower PF limit.
The load kW is too
low.
• Control connections
from bank outputs to
contactor coils are not
proper.
• This is OK condition .
•Check control supply
and connections from
Bank outputs to
contactors coils.
Some Capacitor
banks are
declared as faulty
even if they are
checked to be OK.
•Individual step health
monitoring is enabled,
and tolerance limits set
are too stringent.
• Load kW & THD
factor is continuously
•Set the tolerance limits
for individual steps
monitoring appropriately.
• With continuously
fluctuating Load kW &
THD can cause some
Troubleshooting procedure
Power Factor Controller APFC 06
- 30 -
factor is continuously
fluctuating.
THD can cause some
errors in individual step
kVAr measurement.
Under this condition, best
is to keep this feature
disabled.
APFC-06
resets
occasionally on
turning OFF of any
contactor.
• The contactor supply
phase may be the
same as used for
APFC
06
auxiliary supply.
• R-C Snubbers are not
put in parallel with
contactor coils.
• Use different phases for
control supply of
contactors and for
APFC
06
supply.
• Usage of R-C Snubbers
are strongly
recommended.
APFC-06
Functioning
• Verify EACH User
Settable Parameter is
right as per Panel
Design. Check with
commissioning records.
• Set again the
Parameter(s) which did
not match the design &
save all settings again.
