Mitsubishi Electric FR-F720P-0.75K to 110K 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 is
2
generated from machines.
3
Response is slow.
Return time (response time)
4
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.
Set Pr.820 and Pr.821 higher.
If acceleration is slow, raise the setting by 10%s and set a value that
Pr.820 satisfies the 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
Pr.821 that satisfies the following condition: The setting where overshoots stop
occurring × 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: The setting immediately before vibration/noise starts occurring ×
Pr.820
0.8 to 0.9
If overshoots occur, raise the setting by double the setting and set a value
Pr.821 that satisfies the following condition: The setting where overshoots stop
occurring × 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 following condition: The setting immediately before vibration/noise starts
Pr.820
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.
(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.
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 91.)
(1) -2 Capacity shortage
(2) Speed deviation occurs under P (proportional) control
when the load is heavy. Select PI control.
(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 91.)
(3) Adjust Pr.820 and Pr.821 (Refer to page 84.)
(1) Set Pr.820 lower and Pr.821 higher.
(2) Check the wiring.
4
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