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12.8. Troubleshooting
12.8.1. Troubleshooting
The following table lists a series of typical service conditions, to help you understand and solve hypothetical faults or malfunctions.
N.B.:
1. Before consulting the following table, check for a few seconds for any optical signals provided by the LEDs.
2. FN indicates the normal operation of the PR121/P.
3. If the following suggestions fail to solve the problem, please contact the ABB SACE customer support service.
4. If possible, use the external communication units and supply a report downloaded by means of Ekip Connect.
N° Situation
1 The trip test cannot be run
2 Trip times lower
than expected
3 Trip times higher
than expected
4 Rapid trip, with I3=Off
5 Earth fault current beyond
threshold
6 Expected trip does not happen Function OFF
7 LEDs irregularly turned on
8 Unexpected trip
9 L LED (orange) fl ashing
12.8.2. In the case of a fault
WARNING: If the PR121/P is suspected of being faulty, if there are signs of malfunctions or it has generated an
unexpected trip, we advise you to strictly follow the recommendations below:
1. Press the "i Test" button (within 48 hours of CB opening or within 24 hours if the operating temperature is in the -40°..-25°
range) and make a note of the led that comes on, the type of CB, the number of poles, any accessories connected, In, Serial
Number. After 48 or 24 hours, depending on the case, the data are not cancelled. Just the LED display is inhibited.
2. Prepare a brief description of the opening (what LEDs were displayed?, when did it happen?, how many times?, was it always
under the same conditions? what type of load? what current? is the event reproducible?).
3. Send/communicate all the information collected, together with the circuit diagram for the circuit-breaker, to your nearest ABB
Customer Support service.
The more the information given to the ABB Customer Support service is complete and accurate, the easier the technical analysis
on the problem encountered will be, enabling us to take all action to help the user without delay.
WARNING: Letting a switch run with a fault that has not been remedied may lead to an apparatus malfunction
or shutdown. Remove the apparatus immediately until it can be inspected or repaired if this situation may lead
to personal injury, damage or is otherwise critical.
Model
L6555
Possible causes
1. The busbar current is è > 0
2. The TC is not connected
3. PR030/B is not connected
1. Threshold too low
2. Curve too low
3. Incorrect neutral selection
1. Threshold too high
2. Curve too high
3. Curve type "t=k/I
2"
4. Incorrect neutral selection
Iinst tripped
G function automatically inhibited but no
trip occurs
Suggestions
1. Normal operation (FN)
2. Check TC connection (see par. 12.6.3)
3. Connect the PR030/B unit
1. Correct threshold
2. Correct curve
3. Correct neutral adjustment
1. Correct threshold
2. Correct curve
3. Select curve type "t=k"
4. Correct neutral adjustment
FN short-circuit with high I
FN
FN enable protection function
see par. 12.3.2
see par. 12.3.2
FN
Apparatus
Doc. no.
1SDH000460R0002
Scale
Emax
Page No
46/74
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