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9440300990 Rev J
Configuration
DECS-250
Soft Start
During startup, the soft start function prevents voltage overshoot by controlling the rate of generator
terminal voltage buildup (toward the setpoint). Soft start is active in AVR, FCR, and FVR regulation
modes. Soft start behavior is based on two parameters: level and time. The soft start level
A
is expressed
as a percentage of the nominal generator terminal voltage and determines the starting point for generator
voltage buildup during startup. The soft start time
B
defines the amount of time allowed for the buildup of
generator voltage during startup. Two groups of soft start settings (primary and secondary) provide for
independent startup behavior which is selectable through BESTlogic™
Plus
.
Field Flashing
To ensure generator voltage buildup, the field flashing function applies and removes flashing power from
an external field flashing source. Field flashing is active in AVR, FCR, and FVR control modes. During
system startup, the application of field flashing is based on two parameters: level and time.
The field flash dropout level
C
determines the level of generator voltage where field flashing is withdrawn.
In AVR mode, the field flash dropout level is expressed as a percentage of the generator terminal voltage.
In FCR mode, the level is expressed as a percentage of the field current. And in FVR mode, the level is
expressed as a percentage of the field voltage.
The field flash time
D
defines the maximum length of time that field flashing may be applied during startup.
To use the field flashing function, one of the DECS-250 programmable contact outputs must be
configured as a field flashing output.
Figure 151. Startup Function Settings
A
Soft Start Level (%)
: Adjustable from 0 to 90% in 1% increments.
B
Soft Start Time (s)
: Adjustable from 1 to 7,200 seconds in 1 second increments.
C
Field Flash Dropout Level
: Adjustable from 0 to 100% in 1% increments.
D
Maximum Field Flash Time
: Adjustable from 1 to 50 seconds in 1 second increments.
Device Information
BESTCOMSPlus Navigation Path:
Settings Explorer, General Settings, Device Info
HMI Navigation Path:
Settings, General Settings, Device Information, DECS-250
Device information includes user-assigned identification labeling and read-only firmware version
information and product information. Device information (Figure 152) is provided for the DECS-250, CEM-
2020 Contact Expansion Module, and AEM-2020 Analog Expansion Module.
Summary of Contents for DECS-250
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Page 6: ...iv 9440300990 Rev J Revision History DECS 250 ...
Page 16: ...xiv 9440300990 Rev J Contents DECS 250 ...
Page 20: ...4 9440300990 Rev J Introduction DECS 250 ...
Page 28: ...12 9440300990 Rev J Power Stage DECS 250 ...
Page 32: ...16 9440300990 Rev J Voltage and Current Sensing DECS 250 ...
Page 40: ...24 9440300990 Rev J Synchronizer DECS 250 ...
Page 52: ...36 9440300990 Rev J Auxiliary Control DECS 250 ...
Page 56: ...40 9440300990 Rev J Contact Inputs and Outputs DECS 250 ...
Page 84: ...68 9440300990 Rev J Limiters DECS 250 ...
Page 114: ...98 9440300990 Rev J Power System Stabilizer DECS 250 Figure 96 PSS Parameter Settings ...
Page 124: ...108 9440300990 Rev J Stability Tuning DECS 250 ...
Page 126: ...110 9440300990 Rev J Mounting DECS 250 Figure 103 Overall and Projection Mounting Dimensions ...
Page 127: ...9440300990 Rev J 111 DECS 250 Mounting Figure 104 DECS 250 Escutcheon Plate Dimensions ...
Page 198: ...182 9440300990 Rev J Timekeeping DECS 250 ...
Page 210: ...194 9440300990 Rev J CAN Communication DECS 250 ...
Page 304: ...288 9440300990 Rev J Maintenance DECS 250 ...
Page 316: ...300 9440300990 Rev J Specifications DECS 250 ...
Page 334: ...318 9440300990 Rev J Analog Expansion Module DECS 250 ...
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