Mitsubishi Electric FR-A800, Instruction Manual

Page: 288 / 1042

Speed control under Real sensorless vector control, vector control, PM sensorless vector control Parameters
5 - 108
4
Motor speed
fluctuates.
Speed command varies.
앫
Check that the speed command sent from the controller is
correct. (Take EMC measures.)
앫
Set Pr. 72 "PWM frequency selection" lower.
앫
Set Pr. 822 "Speed setting filter 1" higher (page 5-399).
Torque shortage.
앫
Raise the torque limit.
(Refer to the torque limit for speed control on page 5-84.)
앫
Perform speed feed forward control.
Speed control gain is not
suitable for the machine.
(Resonance occurs.)
앫
Perform easy gain tuning.
앫
Adjust Pr. 820 "Speed control P gain 1" and Pr. 821 "Speed
control integral time 1".
앫
Perform speed feed forward control or model adaptive speed
control.
5
Hunting (vibration
or acoustic noise)
occurs in the motor
or the machine.
Speed control gain is too
high.
앫
Perform easy gain tuning.
앫
Set Pr. 820 "Speed control P gain 1" lower and Pr. 821 "Speed
control integral time 1" higher.
앫
Perform speed feed forward control or model adaptive speed
control.
Torque control gain is
too high.
앫
Set Pr. 824 "Torque control P gain 1 (current loop proportional
gain)" lower.
Motor wiring is incorrect.
앫
Check the wiring.
6
Acceleration/
deceleration time is
different from the
setting.
Torque shortage.
앫
Raise the torque limit.
(Refer to the torque limit for speed control on page 5-84.)
앫
Perform speed feed forward control.
Load inertia is too high.
앫
Set acceleration/deceleration time suitable for the load.
7
Machine movement
is unstable.
Speed control gain is not
suitable for the machine.
앫
Perform easy gain tuning.
앫
Adjust Pr. 820 and Pr. 821.
앫
Perform speed feed forward control or model adaptive speed
control.
Response is slow
because of the inverter's
acceleration/
deceleration time
setting.
앫
Set the optimum acceleration/deceleration time.
8
Rotation ripple
occurs during the
low-speed
operation.
High carrier frequency is
affecting the motor
rotation.
앫
Set Pr. 72 "PWM frequency selection" lower.
Speed control gain is too
low.
앫
Set Pr. 820 "Speed control P gain 1" higher.
Parameters referred to
Pr. 3 Base frequency => page 5-654
Pr. 19 Base frequency voltage => page 5-654
Pr. 72 PWM frequency selection => page 5-219
Pr. 80 Motor capacity => page 5-56
Pr. 81 Number of motor poles => page 5-56
Pr. 125 Terminal 2 frequency setting gain frequency => page 5-401
Pr. 126 Terminal 4 frequency setting gain frequency => page 5-401
Pr. 359 Encoder rotation direction => page 2-73
Pr. 369 Number of encoder pulses => page 2-73
Pr. 822 Speed setting filter 1 => page 5-399
Pr. 824 Torque control P gain 1 (current loop proportional gain) => page 5-144
Pr. 851 Control terminal option-Number of encoder pulses => page 2-73
Pr. 852 Control terminal option-Encoder rotation direction => page 2-73
No. Condition Cause Countermeasure
Tab. 5-39: Troubleshooting (2)