Faults Shown - Kohler 40-150EOZDJ Installation Manual

9.4.2

Faults Shown

Step Potential Cause
Fault: System Voltage Mismatch Between Generators
1 System voltage is not
equivalent
Fault: System Frequency Mismatch Between Generators
1 System frequency is not
equivalent
Fault: Phase Connection Mismatch Between Generators
1 Phase connection is not
equivalent
Fault: Live Bus Sensed When Dead Bus Expected
1 Bus is considered to be
live
2 Bus sensing is not
connected
Fault: Close Attempt
Fault: Fail to Close
1 Breaker is unable to
close
2 Trip is not removed from
the circuit breaker
3 CB trip relay is wired as
normally open
4 Incorrect wiring between
the CB trip relay and the
trip coil on the breaker
5 Close is not applied to
the circuit breaker
6 Breaker is not charged
TP-6862 6/14
Explanation
One of the controllers on the network is
configured differently than the other
controllers. This will inhibit any of the
generators from closing to the bus.
One of the controllers on the network is
configured differently than the other
controllers. This will inhibit any of the
generators from closing to the bus.
One of the controllers on the network is
configured differently than the other
controllers. This will inhibit any of the
generators from closing to the bus.
The controller is measuring voltage on the
paralleling bus. This will inhibit the breaker
from closing.
The controller may see voltage on the
paralleling bus when the generator is
operating and the bus sensing is
disconnected.
The controller is attempting to close the
circuit breaker but the breaker is not
closing.
The controller is attempting to close the
circuit breaker but the breaker is not
closing because the trip coil is still
energized.
The controller is expecting that the trip on
the circuit breaker is a normally-closed
contact. This is intentional as it holds a trip
on the breaker if the controller is removed.
The CB trip relay is operating correctly but
the trip coil on the breaker is remaining
energized. This could be due to incorrect
wiring between the generator controller and
the circuit breaker.
The breaker trip is removed but the
controller is not able to close the breaker.
The breaker is receiving the signal to close
but the energizing spring is not charged.
Troubleshooting
Verify the system voltage of all the
generators match the requirements of the
site.
Verify the system frequency of all the
generators match the requirements of the
site.
Verify the phase connection of all the
generators match the requirements of the
site.
Check bus for residual voltage (sometimes
induced by large transformers or motors).
Possibly, adjust the Dead Bus Threshold to
accommodate the residual voltage.
Verify the bus sensing wiring is connected
to the load side of the motor-operated
breaker for this generator.
Watch the ready flag on the motor operator
of the circuit breaker. If it indicates not
ready when the engine is stopped and
toggles to the ready state when the
generator is trying to close the breaker, the
trip coil is acting correctly. Continue at
Step 5 otherwise, continue on to Step 2.
If the ready flag of the motor operator
indicates ready when the engine is
stopped, continue at Step 3 otherwise,
continue on to Step 4.
Verify the CB trip relay is wired to hold a
trip on the breaker when the relay is not
energized.
Verify the wiring to the circuit breaker.
Verify the wiring between the generator
controller and the circuit breaker close coil.
Check the close coil to ensure that it is not
defective.
Verify the motor operator is receiving
voltage at the appropriate contacts to allow
it to wind the spring.
Section 9 Paralleling Generator Sets 65