Rockwell Automation 7000 PowerFlex Medium Voltage (B Frame) Commissioning - ForGe (PanelView 550) - Manual (Page 107)

Rockwell Automation Publication 7000-IN006B-EN-P - May 2013 103
Commissioning the Drive Chapter 5
8. Set parameter SpdReg Bandwidth to the normal operating value. Confirm
that the response time is equal to the inverse of the speed regulator
bandwidth and that there is minimal overshoot. For example, if the speed
regulator bandwidth is set to 2 rad/sec, the speed should rise to 63% of its
final value in 0.5 second.
9. Set parameter Speed Ref Step to zero and stop the drive.
Calculating Total Inertia
If you cannot measure the system inertia, calculate it (if you know the motor’s
inertial moment motor and load). The value of parameter Total Inertia is the time
required to accelerate the motor and load to rated speed when applying the rated
torque. Use the following calculation:
If there is a gearbox between the motor and load, refer the inertia of the load to
the motor side of the gearbox.
Flux Speed Regulator (Synchronous Motors)
Configuring the Field Current Reference
Use a current-regulated field supply to excite the synchronous motor: either a dc
supply for a slip ring or DC brushless machine, or a three phase ac supply for an
AC brushless machine. The drive provides an analog current reference as an input
to the field supply. The analog current reference has a range of 0-10V, where 0V
corresponds to zero field current and 10V corresponds to maximum field current.
Adjust the scaling of the analog current reference to achieve a linear relationship
between the current reference and the actual field current. Failing to do so may
result in an unstable flux regulator. Adjust the analog output scaling using the
following procedure:
1. Temporarily assign variable Autotune Lmd in Autotuning to the analog
output that controls the field supply (e.g. ACB Port 1).
2. Set the analog output scale parameter (e.g. Anlg Out1 Scale in Analog
Output) to:
Analog Scale = maximum analog input of field supply / 10V
Total inertia = total inertia of motor & load in kg-m 2 X (rated speed in rad/ sec) 2
rated power in watts
—OR—
Total inertia = 6.21 x 10 -7 total inertia of motor and load in lb-ft2 X (rated speed in rpm) 2
rated power in hp
IMPORTANT Before tuning the FluxSpeed regulator, you must configure the analog output
for the field current reference.