Rockwell Automation 1557 MEDIUM VOLTAGE AC DRIVE - Manual (Page 231)

COMMISSIONING 9-31
1557-UM050F-EN-P – June 2013
3. Commutation Inductance and Current Regulator
It is possible to autotune the commutation inductance and current regulator at the same time using the
following procedure:
1.
Set parameter “Autotune Select” in “P Autotune” to 3. The drive will go into dc current test mode.
2. Start the drive. The commutation inductance autotuning is performed and then the current regulator
autotuning is performed without stopping. When both tests are complete the drive shuts off.
The tests performed are the same as described previously for the commutation inductance and current
regulator autotuning.
4. Stator Resistance
Parameter “R stator “ is used in the hardware reconstruction of the rotor flux. If this parameter is not adjusted
correctly, the resulting distortion in the flux feedback may cause speed feedback or motor synchronization
errors. Stator resistance must be tuned during commissioning because it is effected not only by motor
parameters but also by cable length. Stator resistance can be measured with the motor stationary. The
following Autotune procedure can be used
ATTENTION: In the following steps the rotation of the motor in an
undesirable direction may occur. To guard against possible equipment
damage, it is recommended that the motor be disconnected from the load
and tested for direction prior to proceeding, should the equipment be
sensitive to reverse direction rotation.
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 "P Autotune" to 4.
3. Start the drive. The output frequency ramps up to 2 Hz with the motor current remaining at zero.
The motor current then jumps up to approximately 0.10 pu for less than a second and the drive shuts off. This test
produces a small amount of motor torque and some rotation may occur.
Parameter "Autotune Rs" is set to the measured Stator resistance and parameter "Autotune select" is set to zero.
If the test is successful, parameter " Stator resistance " in "P Motor Model" is set equal to "Autotune Rs". If the
test fails then parameter " Stator resistance " is not changed and a warning is issued indicating the cause of the
failure:
R stator hi - 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 0.20 pu.