Machine Operates Unstably; Speed Control - Mitsubishi Electric FR-V500 Series Instruction Manual

6.4.6

Machine operates unstably

(1) Speed control

The machine operates
unstably.
Is the acceleration/
deceleration time longer
than the setting?
Is the acceleration/
deceleration time extremely
short?
Is the speed control
gain too high.
(Vibration/hunting)
Does speed fluctuation
occur at low speed?
Please contact your sales
representative.
Y
N
Is torque insufficient?
N
Is the load inertia large?
N
Y
Increase the acceleration/
N
deceleration time.
Y
Perform easy gain tuning.
Decrease the speed control
N
proportional gain (Pr. 820).
Increase the speed control
integral time (Pr. 821).
Y
N
Is the carrier frequency
high?
N
Is the speed control
gain low?
N
Is torque insufficient?
N
91
Y
Increase the torque limit value,
or increase the excitation ratio
(Pr. 854).
<Refer to the Instruction Manual
(detailed).>
Increase the motor and inverter
capacities.
Y
Set the acceleration/
deceleration time that matches
the load inertia.
Y
Decrease the carrier
frequency (Pr. 72).
Y
Increase the speed control
proportional gain (Pr. 820).
Decrease the speed control
integral time (Pr. 821).
Y
The possible cause is the
adverse effect of weak
excitation.
Increase the excitation ratio
(Pr. 854). <Refer to the
Instruction Manual (detailed).>
Troubleshooting
6