Rockwell Automation Allen-Bradley PowerFlex 7000, Руководство пользователя

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Rockwell Automation Publication 7000L-UM301F-EN-P - March 2020 253
Commissioning Chapter 4
value. For a very high inertia load such as a large fan, this may be a valid result and
parameter
Total Inertia should be manually set equal to Autotune Inertia .
However, a high inertia measurement could also be produced by a value of
Autotune Trq Stp which is too low.
Running the Load Motor Starting Torque
When starting without an encoder, the drive operates in an open loop mode
below approx. 3 Hz at which point the drive switches to closed loop speed
control. The starting currents are set by three parameters; Torque Commands 0
sensorless (P86), 1 (P87), Torque Command 0 sensorless sets the breakaway
torque and Torque Command 1 sensorless is the torque at the transition point
from open to closed loop. Torque Command Minimum operates in conjunction
with Torque Command 1 to minimize speed overshoot at the transition point. If
you are starting an uncoupled motor, or simply auto-tuning, the default starting
torque values may be sufficient to run the motor. But the defaults are generally
not high enough to start a loaded motor.
Be prepared to have to increase starting torque and ensure Motor Stall faults
during initial operation.
Reaching Specific Load Points
Verify the drive can reach rated speed and load. Monitor the Torque Reference
(P291) and the displayed value of the motor current. If you are running into a
torque limit the Torque Reference will be running near the Torque Limit
Motoring (P84) limit. If you are not realizing rated motor current you may
increase the Torque Limit Motoring slightly. If increasing the Torque Limit
Motoring does not help to increase the motor amps and speed then the drive is
most likely running out of input voltage.
Monitor the Line Voltage pu (P135), and increase the tap setting on the drive
feed if the measured value is less than 1.03 pu. It is desirable to have Line Voltage
pu read in the 1.03 to 1.07 pu range. Alpha Rectifier (P327) should be greater
than 15° while running at rated speed and load, indicating how far forward the
rectifier is phased. The input voltage should be increased by tapping up the
transformer.
Fill in the following table with data from the various load points. If possible,
capture the running parameters with the printer, DriveTools, or Hyperterminal as
a substitute for recording the data in the table below. This should be forwarded
with all commissioning data back to Product Support for future reference.