Troubleshooting In The Speed Control - Mitsubishi Electric FR-F820-00077 Instruction Manual

Speed control under PM motor control
5.3.3

Troubleshooting in the speed control

No. 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.
Motor speed
3
fluctuates.
Hunting (vibration
or acoustic noise)
4
occurs in the motor
or the machine.
Acceleration/
deceleration time is
5
different from the
setting.
Machine movement
6
is unstable.
Rotation ripple
occurs during the
7
low-speed
operation.
Tab. 5-24:
Parameters referred to
Pr. 3
Pr. 19
Pr. 72
Pr. 80
Pr. 81
Pr. 125
Pr. 126
Pr. 822
5 - 58
Cause
Speed command from
the controller is different
from the actual speed.
The speed command is
affected by noise.
The command speed
and the speed
recognized by the
inverter are different.
Torque shortage.
The stall prevention
operation level is
operating.
Only P (proportional)
control is performed.
Speed command varies.
Torque shortage.
Speed control gain is not
suitable for the machine.
(Resonance occurs.)
Speed control gain is too
high.
Torque control gain is
too high.
Motor wiring is incorrect.
Torque shortage.
Load inertia is too high.
Speed control gain is not
suitable for the machine.
Response is slow
because of the inverter's
acceleration/
deceleration time
setting.
High carrier frequency is
affecting the motor
rotation.
Speed control gain is too
low.
Troubleshooting
Base frequency
Base frequency voltage
PWM frequency selection
Motor capacity
Number of motor poles
Terminal 2 frequency setting gain frequency
Terminal 4 frequency setting gain frequency
Speed setting filter 1
PM PM PM
Countermeasure
Check that the speed command sent from the controller is
correct. (Take EMC measures.)
Set Pr. 72 "PWM frequency selection" lower.
Adjust the bias and gain (Pr. 125, Pr. 126, C2 to C7, C12 to C15)
of the speed command again.
Raise the stall prevention operation level.
(Refer to page 5-180.)
Increase the capacity.
Speed deviation occurs under P (proportional) control when
the load is heavy. Select PI control.
Check that the speed command sent from the controller is
correct. (Take EMC measures.)
Set Pr. 72 "PWM frequency selection" lower.
Set Pr. 822 "Speed setting filter 1" higher (page 5-264).
Raise the stall prevention operation level.
(Refer to page 5-180.)
Adjust Pr. 820 "Speed control P gain 1" and Pr. 821 "Speed
control integral time 1".
Set Pr. 820 "Speed control P gain 1" lower and Pr. 821 "Speed
control integral time 1" higher.
Set Pr. 824 "Torque control P gain 1 (current loop proportional
gain)" lower.
Check the wiring.
Raise the stall prevention operation level.
(Refer to page 5-180.)
Set acceleration/deceleration time suitable for the load.
Adjust Pr. 820 and Pr. 821.
Set the optimum acceleration/deceleration time.
Set Pr. 72 "PWM frequency selection" lower.
Set Pr. 820 "Speed control P gain 1" higher.
Parameters
=> page 5-537
=> page 5-537
=> page 5-88
=> page 5-41
=> page 5-41
=> page 5-266
=> page 5-266
=> page 5-264