9-6 9469300994
Troubleshooting DGC-2020HD
Step 2. Ensure that the proper current is present at the DGC-2020HD current sensing inputs 1, 2, 3, 4,
5, and 6.
Step 3. Verify that the current sensing transformer ratios are correct.
Step 4. Confirm that the current sensing transformers are correct and properly installed.
Incorrect Display of Engine RPM
Step 1. Verify that all wiring is properly connected. Refer to the Typical Applications chapter.
Step 2. Verify that the Flywheel Teeth setting is correct.
Step 3. Verify that the prime mover governor is operating properly.
Step 4. Verify that the measured frequency of the voltage at the MPU input (P9-106 and P9-107) is
correct.
Step 5. If the MPU is shared with the governor, verify that the polarity of the MPU input to the governor
matches the polarity of the MPU input to the DGC-2020HD.
DGC-2020HD Indicates Incorrect Power Factor
Check the rotation of the machine and the labeling of the A-B-C terminals. The machine must be rotating
in the same phase sequence as dictated by the generator phase rotation setting for correct power factor
metering. A power factor indication of 0.5 with resistive load present is a symptom of incorrect phase
rotation.
Ground Faults Detected in Ungrounded System Applications
Step 1: Verify that there is no connection from the neutral connection of the generator to the system
ground.
Step 2: Perform insulation resistance tests on the system wiring to check for insulation integrity in the
overall system.
Step 3: If ground faults are detected on a DGC-2020HD in an ungrounded system application, it is
recommended that potential transformers be employed on the voltage sensing inputs to provide
full isolation between the DGC-2020HD and monitored voltage phases.
Step 4: If potential transformers are in place, remove the connectors from the DGC-2020HD one at a
time. If removal of a connector removes the ground fault, check the system wiring to that
connector and out into the system to verify that connections are secure and all wiring insulation
is in good condition.
Generator Breaker and Mains Breaker
Generator Breaker Will Not Close to a Dead Bus
Step 1: Review the description of how the generator breaker logic element functions contained in the
GENBRK logic element description in the BESTlogic™Plus chapter in the Configuration manual.
Step 2: Review the section on breaker close requests in the Breaker Management chapter in the
Configuration manual.
Step 3: Navigate to the Settings, Breaker Management, Breaker Hardware, Gen Breaker screen and
set Dead Bus Closure to Enable.
Step 4: Verify that the Generator status is stable. The breaker will not close if the generator status is
not stable. Check status by using the Metering Explorer in BESTCOMSPlus and verify that
when the generator is running, the Generator Stable status LED is lit. If necessary, modify the
settings on the Settings, Breaker Management, Bus Condition screen.
Step 5: Verify the bus status is Dead. Check status by using the Metering Explorer in BESTCOMSPlus
and verify that when the generator is running, the Bus Dead status LED is lit. If necessary,
modify the settings on the Settings, Breaker Management, Bus Condition screen.
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