Troubleshooting
7-
25
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), C2-01 (S-curve Characteristic Time at Acceleration Start), 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. Alternatively, change the control method selection (A1-
02) to V/f control (0 or 1).
Oscillation and hunting are occurring with V/f control.
The gain adjustment may be insufficient. Reset the gain to a more effective level by adjusting constants C4-02
(Torque Compensation Primary Delay Time Constant), N1-02 (Hunting Prevention Gain), and C3-02 (Slip
Compensation Primary Delay Time) in order. Lower the gain setting and raise the primary delay time setting.
Oscillation and hunting are occurring with V/f w/PG control.
The gain adjustment may be insufficient. Adjust the various types of speed control loop (ASR) gain.
If the oscillation cannot be eliminated in this way, set the hunting prevention selection (constant N1-01) to 0
(disabled) and then try adjusting the gain again.
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.
Oscillation and hunting are occurring with PID control.
If there is oscillation or hunting during PID control, check the oscillation cycle and individually adjust P, I,
and D constants. (Refer to page 6-112.)
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. Alternatively, change the Control Method Selection
(A1-02) to V/f control.
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 problem occurs after performing stationary autotuning, perform rotational
autotuning.
