Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive - Air-Cooled (A Frame) - Manual (Page 224)

4-70 Commissioning
7000A-RM001A-EN-P – January 2011 7000 “A” Frame
Speed Regulator Manual Tuning [Induction Motor]
If it is not possible to tune the speed regulator using the auto-tune
function, then the step response of the speed regulator can be tuned
manually using the following procedure. To obtain accurate results,
the load torque must be steady.
1. Set parameter SpdReg Bandwidth in Speed Control to 1.0
rad/sec.
Speed Control Parameter Screen
2.
Set parameter Total Inertia in Speed Control to an initial value
of 1.0 sec if it is a low inertial application (pumps etc). Set the
parameter to 5.0 seconds if it is a high inertia application (e.g. ID
Fans).
3. Assign parameter Speed Error in the Speed Control group to a
test point e.g. ITP1 on the DPM. This can be done similarly to
the way that the meter assignments were described earlier in the
chapter. Then it can be displayed on your oscilloscope.
4. Adjust the reference command to a value around the middle of
the operating speed range.
5. Start the drive and wait for it to accelerate to the commanded
speed.
6.
Set parameter Speed Ref Step in Speed Control to 0.8 Hz. The
drive speed will step up and down by this amount at regular
intervals. The step of 0.8 Hz corresponds to 0.8V or 800mV on
the test point. To capture the error set the scope at
200mV/division and 200msec/division. Trigger the scope on
negative edge as shown in Figure.
7.
Adjust the value of parameter Total Inertia until the speed rises
to approximately 63% of its final value in 1 second as shown in
the figure. If the response time is too fast, it indicates that Total
Inertia is set too high and should be decreased. If the response is
too slow, then Total Inertia is set too low and should be
increased.
Tuning Procedure (cont.)