TP-6953 7/19 125Section 7 Troubleshooting
Step Potential Cause
Explanation Troubleshooting
Fault: CB Status
Warning: Bus Sensing Not Connected
1 Breaker status
feedback is not valid,
no bus sensing
The breaker closes but the controller does not see a change in status. The
controller cannot see the bus is energized as the bus sensing is not connected
correctly on this generator, but another generator is connected.
Verify the wiring on the circuit breaker to ensure that it is connected
correctly. Verify bus wiring for this generator.
Fault: CB Status or Continuous Breaker Cycling
1 Breaker status
feedback is not valid
The breaker closes but the controller does not see a change in status. The
controller sees the bus is now live.
Verify the wiring on the circuit breaker to ensure that it is connected
correctly.
7.7 Paralleling Troubleshooting—When Breaker Does Close to Bus
7.7.1 Faults Shown
Step Potential Cause
Explanation Troubleshooting
Fault: Close Attempt
Fault: Fail to Close
1 Breaker status
feedback is not valid,
no bus sensing
The breaker closes but the controller does not see a change in status. The
controller cannot see the bus is energized as the bus sensing is not connected
correctly on any generators on the network.
Verify the wiring on the circuit breaker to ensure that it is connected
correctly. Verify bus wiring for all nodes. Verify the generator output is
connected to the line side of the generator breaker.
Fault: CB Status
1 Breaker status
feedback is not
connected
The breaker closes but the controller does not see a change in status. The
controller sees the bus is now live.
Verify the wiring on the circuit breaker to ensure that it is connected
correctly.
2 Breaker status is short
circuited
The controller sees the breaker is closed even when it is not trying to open it. Verify connection of the breaker status wiring at the circuit breaker.
3 Breaker status
feedback is connected
to the wrong contacts
The controller sees open status for the breaker after telling it to close, closed
status after telling it to open.
The controller is expecting the breaker status to be an “A” contact. Verify
the circuit breaker auxiliary contacts are either:
11 and 14
21 and 24
31 and 34 or
41 and 44.
If the breaker status contacts are removable, make sure that they are
inserted in one of the OF slots and that the wires go to 1 and 4.
4 Breaker status
feedback is connected
toalatchingcontact
The breaker status indicated that it closed when it was triggered to close but it
did not indicate that it was open when the breaker opened. This fault will only
occur if the bus sensing is connected correctly (the controller sees the voltage
go to 0 when the breaker is triggered to open).
Verify the breaker status input to the controller is connected directly to an
auxiliary contact on the circuit breaker.
Fault: Bus Phase Rotation Mismatch
1 All of the bus sensing
wires are incorrectly
connected
The bus sensing wires must be connected to phase A, phase B, and phase C
of the bus. If any two connections are reversed, the controller can detect the
reversed connections. This fault will only occur if all three wires are incorrectly
connected.
Verify the bus metering connections.
2 The phase connections
on the paralleling
breaker are
inconsistent with the
generator
The power leads from the generator to the paralleling circuit breaker must be
connected consistently. Phase A from the generator must go to phase A of the
line side of the paralleling (motor operated) breaker, phase B from the
generator to phase B of the breaker and phase C of the generator to phase C of
the breaker.
Verify the output cable connections.
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