Basler Electric DGC-2020 - Manual (Page 358)

close commands simultaneously. The breaker will not change state if it is being commanded to
open and close at the same time.
Step 7: Verify the breaker is receiving a close command. Breaker close command sources are:
•
The DGC-2020 itself when the automatic transfer (ATS) feature is enabled.
•
The DGC-2020 itself when the RUN WITH LOAD logic element receives a Start pulse
in the programmable logic.
•
The DGC-2020 itself when started from a Demand Start as part of demand start/stop
and sequencing.
•
The DGC-2020 itself when started from the Exercise Timer and the Run with Load box
is checked in the Generator Exerciser settings.
•
Manual Breaker Close Input Contacts applied to the Open and Close inputs on the left
side of the Generator Breaker logic element in the programmable logic.
Step 8: Verify the wiring to the breaker from the DGC-2020. If it seems OK, you can do a manual close
and open by modifying the programmable logic. Map some unused outputs to the OPEN and
CLOSE outputs from the Gen Breaker Block in the programmable logic. Map a virtual switch to
the logic output that would normally be the breaker close output. Map another virtual switch to
the logic output that would normally be the breaker close output. Connect with
BESTCOMSPlus
®, and exercise the virtual switches using the Control panel located in the
Metering Explorer. Never turn open and close on at the same time. This could damage the
breaker and/or motor operator. If everything is working as expected, restore the logic to its
original diagram.
Generator Breaker Will Not Close to a Live Bus
Step 1: Review the description of how the generator breaker logic element functions contained in the
GENBRK logic element description in Section 5, BESTlogicPlus Programmable Logic.
Step 2: Review the section on breaker close requests in Section 3, Functional Description, Breaker
Management.
Step 3: Verify that the Generator status is stable. The breaker will not close if the generator status is
not stable. Check status using the Metering Explorer in BESTCOMSPlus
® and verify that when
the generator is running, the GEN STABLE status LED is lit. If necessary, modify the settings
on the SETTINGS > BREAKER MANAGEMENT > BUS CONDITION DETECTION screen.
Step 4: Verify that the Bus status is stable. The breaker will not close if the bus is not stable, check
status using the Metering Explorer in BESTCOMSPlus ® and verify that when the generator is
running, the BUS STABLE status LED is lit. If necessary, modify the settings on the SETTINGS
> BREAKER MANAGEMENT > BUS CONDITION DETECTION screen.
Step 5: Verify the connections in BESTlogicPlus Programmable Logic to the generator breaker logic
element. The Status input must be driven by an “A” or normally open contact from the generator
breaker. The OPEN and CLOSE command inputs on the left side of the logic block are inputs
for open and close commands. These can be wired to physical inputs if it is desired to have
open and close command switches. If they are wired, they must either be pulsed inputs, or
some logic must be employed so that the open and close command inputs are never driven at
the same time. If these are both driven at the same time, the breaker is receiving open and
close commands simultaneously. The breaker will not change state if it is being commanded to
open and close at the same time.
Step 6: Verify the breaker is receiving a close command. Breaker close command sources are:
•
The DGC-2020 itself when the automatic transfer (ATS) feature is enabled.
•
The DGC-2020 itself when the RUN WITH LOAD logic element receives a Start pulse
in the programmable logic.
•
The DGC-2020 itself when started from a Demand Start as part of demand start/stop
and sequencing.
•
The DGC-2020 itself when started from the Exercise Timer and the Run with Load box
is checked in the Generator Exerciser settings.
•
Manual Breaker Close Input Contacts applied to the Open and Close inputs on the left
side of the Generator Breaker logic element in the programmable logic.
Step 7: Verify the synchronizer is operating properly; refer to the synchronizer portion of the
troubleshooting steps.
8-4 DGC-2020 Maintenance and Troubleshooting 9400200990 Rev X