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Oscillation and hunting are occurring with open-loop vector control.
The gain adjustment may be insufficient. Reset the gain to a more effective level by adjusting constants C4-02
(torque compensation time constant), n2-01 (Speed feedback detection control (AFR) gain), and C3-02 (Slip
Compensation Primary Delay Time) in order. Lower the gain setting and raise the primary delay time setting.
Vector control will not perform if autotuning has not been performed. Perform autotuning separately for the
motor, or set the motor constants through calculations.
Oscillation and hunting are occurring with flux vector control.
The gain adjustment is insufficient. Adjust the various gains for speed control (ASR). If the oscillation points
overlap with those of the machine and cannot be eliminated, increase the primary delay time constant for
speed control (ASR) in C5-06 and then readjust the gains.
If autotuning is not performed, proper performance cannot be achieved for vector control. Perform autotuning
or set the motor constants according to calculations.
Autotuning has not been performed with vector control.
Vector control will not perform if autotuning has not been performed. Perform autotuning separately for the
motor, or set the motor constants through calculations.
If the Torque Generated for the Motor is Insufficient (Insufficient Power)
If autotuning has not been performed, or the control method has been changed since last performing autotun-
ing, perform autotuning.
If the Motor Rotates Even When Inverter Output is Stopped
If the motor rotates even when the Inverter output is stopped, the DC injection braking is insufficient. If the
motor continues operating at low speed, without completely stopping, and after a deceleration stop has been
executed, it means that the DC injection braking is not decelerating enough. Adjust the DC injection braking
as follows:
•
Increase the constant b2-02 (DC Injection Braking Current) setting.
•
Increase the constant b2-04 (DC Injection Braking (initial excitation) Time at Stop) setting.
If OV is Detected When the Fan is Started, or Fan Stalls
Generation of OV (main circuit voltage) and stalling can occur if the fan is turning when it is started. The DC
injection braking is insufficient when starting.
This can be prevented by slowing fan rotation by DC injection braking before starting the fan. Increase the
constant b2-03 (DC injection braking time (initial excitation) at start) setting.
