Omron SYSDRIVE RV Series User Manual page 446

There may be resonance between the mechanical system's characteristic frequency and the
carrier frequency.
If the motor is running with no problems and the machinery is oscillating with a high-pitched whine, it may
indicate that this is occurring. To prevent this type of resonance, adjust the carrier frequency with parameters
C6-02 to C6-05.
There may be resonance between a machine's characteristic frequency and the output fre-
quency of the Inverter.
To prevent this from occurring, either use the jump frequency functions in parameters d3-01 to d3-04 or install
rubber padding on the motor base to reduce oscillation.
The motor vibrates strongly and won't operate normally.
This may be caused by open phases in the motor output. Failure in one or two of the phases in a three-phase
motor output will cause extremely strong vibration and prevent the motor from operating. Check for a faulty
motor power line or disconnection. The same condition will also occur if the Inverter's output transistor is
open and damaged. Check the balance of the Inverter output voltage.
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 parameters 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 parameters 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 parameters 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 (parameter 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 parameters 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 parameters. (Refer to page 6-146.)
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