Rockwell Automation GV3000/SE AC Gen. Purpose and Vector Drive Software Start-Up and Ref. Manual - Manual (Page 166)

4-80 GV3000/SE AC Drive Software Reference, Version 6.06
For special motors or for motors with base speeds < 1150 RPM, the rotor time
constant must be calculated by evaluating equivalent motor circuit data as shown in
figure 4.14.
To calculate the rotor time constant, use the following formula:
Rotor time constant = L / R2
Where: L = Lm + L2
Lm = Xm / 2 x 3.14 x 60
L2 = X2 / 2 x 3.14 x 60
Fast Flux-Up Feature (SVC Only)
The fast flux-up feature, available for drives configured for SVC operation only,
significantly reduces the delay between the initiation of a run command and the actual
motor shaft turning.
Setting U.021 to 0 enables the fast flux-up feature. Parameter U.031 (SVC Sync
Direction) must be set to OFF to use this feature.
Note that this parameter is not functional in versions 6.0 through 6.05.
U.021 Rotor Time Constant / Fast Flux Up
This parameter
determines the
performance of the
magnetizing current
regulator.
For most
applications, it is
recommended that
this parameter not be
changed.
For SVC operation,
this parameter is
used to enable the
fast flux-up feature.
Parameter Range: 0 to 9999 ms
Default Setting: Power Module-dependent, see Appendix C
Parameter Type: Tunable
Refer also to parameters: N/A
Figure 4.14 – Motor Equivalent Circuit Diagram for Calculating Rotor Time Constant
5 ; ;
5 ;P
5HVLVWDQFH
5 6WDWRU
5 6WDWRU
,QGXFWDQFH
; 6WDWRU
; 5RWRU
;P 0DJQHWL]LQJ