Mitsubishi Electric FR-F700PJ Instruction Manual page 96

 Adjust in the following procedure:
1) Change the Pr.820 setting while checking the conditions.
2) If it can not be adjusted well, change Pr.821 setting, and perform 1) again.
·
No. Movement condition
1
Load inertia is too high.
Vibration or acoustic noise
2
are generated from
machines.
3
Response is slow.
Return time (response
4
time) is long.
Overshoots or unstable
5
movements occur.
(2) Troubleshooting
Condition
Motor does not run at the
correct speed.
1
(Command speed and
actual speed differ.)
The speed does not
2 accelerate to the command
speed.
3 Motor speed fluctuates.
Hunting (vibration or
4 acoustic noise) occurs in
the motor or the machine.
Acceleration/deceleration time
5
is different from the setting.
Machine movement is
6
unstable.
Rotation ripple occurs
7 during the low-speed
operation.
Set Pr.820 and Pr.821 higher.
If acceleration is slow, raise the setting by 10%s and set a value that satisfies the
Pr.820 following condition: The setting immediately before vibration/noise starts
occurring  0.8 to 0.9
If overshoots occur, raise the setting by double the setting and set a value that
satisfies the following condition: The setting where overshoots stop occurring 
Pr.821
0.8 to 0.9
Set Pr.820 lower and Pr.821 higher.
Lower the setting by 10%s and set a value that satisfies the following condition:
Pr.820
The setting immediately before vibration/noise starts occurring  0.8 to 0.9
If overshoots occur, raise the setting by double the setting and set a value that
satisfies the following condition: The setting where overshoots stop occurring 
Pr.821
0.8 to 0.9
Set Pr.820 higher.
If acceleration is slow, raise the setting by 5%s and set a value that satisfies the
Pr.820 following condition: The setting immediately before vibration/noise starts
occurring  0.8 to 0.9
Set Pr.821 lower.
Lower Pr.821 by half the current setting and set a value that satisfies the following condition:
The setting immediately before overshoots or unstable movements stop occurring  0.8 to 0.9
Set Pr.821 higher.
Raise Pr.821 by double the current setting and set a value that satisfies the following condition:
The setting immediately before overshoots or unstable movements stop occurring  0.8 to 0.9
Possible cause
(1) Speed command from the
controller is different from the
actual speed.
The speed command is
affected by noise.
(2) The command speed and the
speed recognized by the
inverter are different.
(1) Torque shortage
Stall prevention operation is
activated.
(2) Only P (proportion) control is
performed.
(3) Speed control gain is too low.
(1) Speed command varies.
(2) Torque shortage
(3) Speed control gain is not
suitable for the machine.
(Resonance occurs.)
(1) Speed control gain is too high.
(2) Motor wiring is incorrect.
(1) Torque shortage
(2) Load inertia is too high.
(1) Speed control gain is not
suitable for the machine.
(2) Response is slow because of
the inverter's acceleration/
deceleration time setting.
(1) High carrier frequency is
affecting the motor rotation.
(2) Speed control gain is too low.
IPM motor control <IPM>
Adjustment method
Countermeasure
(1) Check that the speed command sent from the controller is
correct. Lower Pr. 72 PWM frequency selection.
(2) Adjust bias and gain (Pr.125, Pr.126, C2 to C7) of the speed
command again.
(1) -1 Raise the stall prevention operation level. (Refer to page
96.)
(1) -2 Capacity shortage
(2) Speed deviation occurs under P (proportional) control
when the load is heavy. Select PI control.
(3) Set Pr. 820 higher.
(1) -1 Check that the speed command sent from the
controller is correct. (Take EMC measures.)
(1) -2 Lower Pr.72 PWM frequency selection.
(2) Raise the stall prevention operation level. (Refer to page 96.)
(3) Adjust Pr. 820 and Pr. 821 (Refer to page 90.)
(1) Set Pr. 820 lower and Pr. 821 higher.
(2) Check the wiring.
(1) Raise the stall prevention operation level. (Refer to page 96.)
(2) Set acceleration/deceleration time suitable for the load.
(1) Adjust Pr. 820 and Pr. 821 (Refer to page 90.)
(2) Set the optimum acceleration/deceleration time.
(1) Lower Pr. 72 PWM frequency selection.
(2) Raise Pr. 820 Speed control P gain 1.
4
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