Rockwell Automation Publication 1407-UM002B-EN-P - February 2019
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CGCM-DLR Unit Operation
Chapter
3
Cross-current
The CGCM-DLR unit senses reactive differential current through properly
connected current transformers that are typically installed on the B-phase output
leads of each paralleled generator.
Typical Cross-current CT Locations and Polarity
for more
information.
Line current inputs are galvanically isolated via CTs internal to the CGCM-DLR
unit. The CGCM-DLR unit accepts either 1 A or 5 A current inputs. The
cross-current input terminals are labeled ID(+)5A, ID(+)1A, and ID(-).
Auxiliary Input
This input is an analog voltage (-10…10V DC), and provides a means to adjust
remotely the regulation point of the generator. Resistive isolation is provided by
using differential amplifiers.
The auxiliary input terminals are labeled VREF(+) and VREF(-).
Power Inputs
The unit has two types of power inputs: control power inputs and excitation
power inputs.
Control Power Input
The CGCM-DLR unit operates from a nominal 24V DC supply that is
connected to the control power inputs. The control power input is
diode-protected to help protect against equipment damage due to improper
polarity of the applied power.
The control power inputs are labeled BAT(+) and BAT(-).
Excitation Power Input
The CGCM-DLR unit accepts either 3-phase or single phase excitation power.
Excitation power can be obtained from the generator or the utility via shunt
excitation (SE) or from the generator prime mover via a Permanent Magnet
Generator (PMG).
for details on connections for SE or PMG operation.
The excitation power input terminals are labeled PMG A, PMG B, and PMG C.