Rockwell Automation GV3000/SE 230VAC 1-20 HP GP & Vector Drive Ver. 6.04 Software Start-Up and Ref. - Manual (Page 168)

4-82 GV3000/SE 230 VAC Drive, Software Reference Version 6.04
U.021 Rotor Time Constant
This parameter
determines the
performance of the
magnetizing current
regulator.
For most
applications, it is
recommended that
this parameter not be
changed.
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.
Parameter Range: 100 to 9999 milliseconds
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
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
Note that this parameter is not functional in version 6.0 and later. It is maintained
for backward compatibility to previous firmware versions.
R1 X1 X2
Xm R2
Resistance
R1 = Stator
R2 = Stator Inductance
X1 = Stator
X2 = Rotor
Xm = Magnetizing