Rockwell Automation WebPak 3000 DC Drive Application Workbook Version 1.1 - Manual (Page 39)

Configuring the Field Current Regulator 5-5
5.2 The Field Feedback
FIELD FEEDBACK (P.589) is derived from field current being fed into an analog input and
scaled by MOTOR HOT FLD AMPS (P.510) and FLD FEEDBACK GAIN ADJ (P.516). Refer to
figure A.12 in Appendix A of the software manual (D2-3444).
þ
To configure field feedback:
▲
Set FLD FEEDBACK GAIN ADJ (P.516).
5.3 Automatic Field Weakening (Spillover Control)
For a typical constant diameter application designed to operate in both a constant
torque and a constant horsepower mode, automatic field weakening (spillover control)
will transition motor operation from constant torque to constant horsepower. Refer to
figure A.12 in Appendix A of the software manual (D2-3444).
þ
To configure automatic field weakening:
▲
Set FIELD AUTO WEAKEN (P.517): The choices are:
DISABLED - The HI limit of the field regulator PI block is set to FIELD DELTA HIGH
LIM (P.587).
ENABLED - A spillover field regulator is provided which uses a PI block with
inputs from FLD WEAKEN THRESHOLD (P.518) and ARMATURE VOLTAGE (P.289).
When P.289 exceeds P.518, the field begins to weaken and the field control
loop begins regulating armature voltage.
The output of the spillover regulator PI block is the input to the HI limit of the
field current regulator PI block. If armature voltage increases, the HI limit
decreases which lowers the field current and, subsequently, lowers armature
voltage back to its threshold value.
Important: When FEEDBACK SELECT (P.200) is set to ARMATURE VOLT , P.517 is
automatically set to DISABLED and cannot be changed.
▲
Set FIELD DELTA HIGH LIM (P.587). It is recommended that this parameter
remain at its default value of 130 degrees.
þ If FIELD AUTO WEAKEN (P.517) = ENABLED :
▲ Set FIELD REF SELECT (P.521) to FULL FIELD to fix the starting point of
the spillover design.
Range: 0.900 to 1.100 P.516 =
Range: DISABLED , ENABLED P.517 =
Range: 0 to 180 DEGREES P.587 = DEGREES
Range: REGISTER , FULL FIELD , FIELD SHAPING P.521 =
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