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9440300990 Rev J
Maintenance
DECS-250
Caution
When energizing the DECS-250 from a low impedance source (such
as a wall outlet), use of an Inrush Current Reduction Module (ICRM) is
recommended to prevent damage to the DECS-250. For a detailed
description of the Inrush Current Reduction Module, refer to Basler
publication 9387900990. ICRM connections are illustrated in
Typical
Connections
.
Cleaning the Front Panel
Only a soft cloth and water-based solutions should be used to clean the front panel. Do not use solvents.
Troubleshooting
The following troubleshooting procedures assume the excitation system components are properly
matched, fully operational, and correctly connected. If you do not obtain the results that you expect from
the DECS-250, first check the programmable settings for the appropriate function.
DECS-250 Appears Inoperative
If the DECS-250 does not power up (no backlighting on front panel display), ensure that the control power
applied to the unit (AC input terminals L and N, DC input terminals BATT+ and BATT–) is at the correct
level. If dc control power is being used, verify that the polarity is correct. Units with style number Lxxxxxx
have an input voltage range of 16 to 60 Vdc. Units with style number Cxxxxxx have an input voltage
range of 90 to 150 Vdc or 82 to 132 Vac (50/60 Hz).
Note
When both ac and dc control power is used, an isolation transformer
must be connected between the ac voltage source and the ac control
power terminals of the DECS-250.
Display Blank or Frozen
If the front panel display (LCD) is blank or frozen (does not scroll), remove control power for about 60
seconds and then reapply control power. If the problem occurred during software uploading, repeat the
upload procedures as described in the associated instructions.
Generator Voltage Does Not Build
Check the DECS-250 settings and system voltages for the following:
a.
Generator potential transformer (PT) primary voltage
b.
Generator PT secondary voltage
c.
AC voltage on the DECS-250 operating (bridge) power terminals (C5 (A), C6 (B), and C7 (C))
Check the DECS-250 soft start bias and soft start time settings. If necessary, increase the generator soft
start bias and decrease the generator soft start time.
If the generator voltage still does not build, increase the value of Kg.
Temporarily disable the overexcitation limiter.
Low Generator Voltage in AVR Mode
Check the following DECS-250 settings and system parameters:
a.
AVR voltage setpoint
b.
Generator potential transformer (PT) primary voltage
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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