Basler Electric DGC-2020 - Manual (Page 363)

relays, not power relays, must be used for this application. Verify the relay contacts are not
affecting the signal.
Step 8: If speed trim is enabled, verify that the speed trim set point is at the correct value for desired
operation.
Generators Do Not Share Load Equally
Step 1: Verify that load sharing is enabled in SETTINGS > BIAS CONTROL SETTINGS > GOVERNOR
BIAS CONTROL SETTINGS > LOAD CONTROL ENABLED.
Step 2: Verify generator breaker status is being correctly received as described in Generator Breaker
Status is not being received by the DGC-2020. If the status is correct, proceed to Step 3.
Step 3: Check the Load Share Line operating voltage range by examining the Min. and Max. Voltage
parameters found in BESTCOMSPlus
® under SETTINGS > MULTIGEN MANAGEMENT >
LOAD SHARE OUTPUT. The range must be the same for all machines in the load share
system.
Step 4: Measure the Load Share line voltage at terminals P2-5 (LS–) and P2-6 (LS+) on the LSM-2020.
The same voltage should be present on each LSM-2020. If not, correct any issues.
Step 5: Examine the FDBK VOLT on the front panel of the DGC-2020 under SETTINGS > SYSTEM
PARAMS > REMOTE MODULE SETUP > LSM SETUP > LSM DEBUG. This is the voltage
read from the load share lines by the DGC-2020. Verify this voltage matches the voltage read
with a voltmeter across LSM-2020 terminals P2-5 (LS–) and P2-6 (LS+). Verify the same FDBK
VOLT is present on all the machines in the load share system. If they are not equal, examine
the load share line wiring and correct any issues.
Step 6: Check if there are any contacts in the load share line path between the LSM-2020s. Any relay
contacts that are used to switch load share lines, governor analog bias signals, or voltage
regulator analog voltage bias signals must use a relay intended for low voltage, low current
applications to preserve signal integrity. Signal relays, not power relays, must be used for this
application. Verify the relay contacts are not affecting the signal.
Step 7: If there are still issues, disconnect the load share line from the LSM-2020. Run the single
machine with load, and verify that it loads and unloads correctly, and runs at the correct speed.
Repeat for each machine.
Step 8: Re-attach load share lines to all LSM-2020s that are part of the load sharing system. Run the
SINGLE machine with load, and verify that it loads and unloads correctly, and runs at the
correct speed. If the machine slows down when the generator breaker is closed, check the load
share line voltage. It should be equal, on a normalized basis, to the normalized kW produced by
the generator. As an example, if the generator is loaded to 50% capacity, the Load Share Line
voltage should be at the midpoint of the range. If it is not, something is driving the load share
line that should not be. The single unit should be the only device driving the load share lines.
Step 9: Disconnect the load share lines from each non-running machine and see if the speed of the
running machine is correct. If a particular LSM-2020 on a non-running machine seems to affect
the performance of the running machine, that LSM-2020 may be damaged such that the Load
Share Line contacts are sticking, causing the LSM-2020 to drive the load share line even
though the generator breaker is open. Tap the relays to see if the problem clears up. If so, a
faulty LSM-2020 relay is indicated. Replace the LSM-2020, or wire in external contacts to
remove the LSM-2020 from the load share system when the generator breaker is closed.
Step 10: If it appears that something is driving the load share line but it is not the LSM-2020 on one of
the non-running units, search for an external device that is driving or loading down the load
share lines.
Step 11: Repeat the preceding 3 steps for each machine.
Load Sharing Works Correctly, but a Single Unit Slows Down
With all units running, load sharing works correctly, but a single unit slows down after the generator
breaker is closed.
Step 1: Disconnect the load share line from the LSM-2020. Run the single machine with load, and
verify that it loads and unloads correctly, and runs at the correct speed. Repeat for each
machine.
9400200990 Rev X DGC-2020 Maintenance and Troubleshooting 8-9