Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) Commissioning - ForGe Control - Manual (Page 99)

Rockwell Automation Publication 7000-IN012B-EN-P - June 2014 99
Commissioning the Drive Chapter 4
You must tune these parameters during commissioning; they are affected by
motor parameters and cable length. Perform the tuning process with the motor
stationary, using the following procedure.
1. Ensure that the motor is stationary. Motor turning may render test results
invalid. It is not necessary to lock the rotor.
2. Set the Autotune Select parameter in Auto-tuning to Motor Impedance.
3. Start the drive. In the first half of the test the output frequency is zero; the
dc current increases to 0.6pu for a few seconds to calculate R Stator, then
decreases to zero.
4. In the second half of the step the output frequency increases to rated
frequency with the dc current equal to 1.0 pu for a few seconds. This test
may produce a small amount of motor torque and some rotation may
occur. This step calculates the L Total Leakage. Decrease the current and
set the Autotune Select parameter to Off.
5. At the end of the R Stator tuning, the R Stator (P#129) in Motor Model is
set equal to Autotune R Stator. If the test fails or the values are out of range,
the interface prompts with a warning indicating the cause of the failure.
6. At the end of the L Leakage tuning, the L total leakage (P#130) in Motor
Model equal to Autotune LLeakage. If the test fails, the interface prompts
with a warning.
The following warnings may 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:
– The motor is much larger than the drive and the motor nameplate
parameters do not correspond to the actual motor ratings.
– Because of the design of the motor, this method of measuring leakage
inductance does not produce a valid result. Obtain the leakage
inductance from the motor data sheet
(1)
, or if this is not possible, set the
L Total Leakage parameter to its default value of 0.20 pu.
ATTENTION: During tuning, the motor may rotate in the wrong direction. To
avoid possible equipment damage, disconnect the motor from the load and test
for direction before proceeding, if the equipment is sensitive to reverse direction
rotation.
(1) , where FLA: Motor Full Load Amps, LRA: Motor Locked Rotor Amps. L
Leakage
FLA
LRA
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