Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive - Air-Cooled (A Frame) - Manual (Page 219)

Commissioning 4-65
7000 “A” Frame 7000A-RM001A-EN-P – January 2011
Motor Impedance Auto-tuning
1.
Ensure that the motor is stationary. If the motor is turning, the
results of the test may be invalid. It is not necessary to lock the
rotor.
2.
Set parameter Autotune Select in Auto-tuning to Motor Impedance.
3.
Start the drive. In the first half of the test the output frequency is
zero and the dc current is ramped to 0.6pu for a few seconds. This
step will calculate R Stator. After this the current is ramped down
to zero.
4.
In the second half of the step the output frequency ramps up to
rated frequency with the dc current equal to 1.0pu for a few
seconds. This test may produce a small amount of motor torque
and some rotation may occur. This step will calculate the L Total
Leakage. The current is ramped down and parameter Autotune
Select is set to Off.
Parameter
Autotune RStator (219) is set to the measured Stator
resistance. R Stator (129) in Motor Model is set equal to Autotune R
Stator. If the test fails or the values are out of range, a warning is
issued indicating the cause of the failure.
Parameter
Autotune LLeakage (220) is set to the measured leakage
inductance. L total leakage (P130) in Motor Model is set equal to
Autotune LLeakage. If the test fails, a warning is issued indicating the
cause of the failure.
Following warnings can occur during this test:
R stator High - this is probably caused by extremely long motor
cables increasing the apparent stator resistance of the motor. The
drive cannot operate with stator resistance greater than 0.50 pu.
L Leakage Low - indicates that the measured leakage inductance
is less than 0.10 pu. Possible causes are:
1. The motor is much larger than the drive and the motor
nameplate parameters do not correspond to the actual motor
ratings.
2. Because of the design of the motor, this method of measuring
leakage inductance does not produce a valid result. The
leakage inductance will have to be obtained from the motor
data sheet, or if this is not possible, parameter L Total Leakage
should be set to its default value of 0.20 pu.