Mitsubishi Electric FR-A700 Instruction Manual page 159

Basic settings
Phenomenon
Acceleration/deceleration
6 time does not match the
setting.
Machine operation is
7
unstable
Speed fluctuates at low
8
speed.
Tab. 5-10: Troubleshooting (3)
FR-A700 EC
Cause
(1) Insufficient torque.
(2) Large load inertia.
(1) The speed control gains do not
match the machine.
(2) Slow response because of
improper acceleration/deceler-
ation time of the inverter.
(1) Adverse effect of high carrier
frequency.
(2) Low speed control gain.
Simple mode parameter list
Countermeasures
(1)-1 Increase the torque limit value. (Refer to
torque limit of speed control in section
6.3.3.)
(1)-2 Perform speed feed foward control.
(2) Set the acceleration/deceleration time that
meets the load.
(1)-1 Perform easy gain tuning. (Refer to sec-
tion 5.1.11).
(1)-2 Adjust Pr. 820, Pr. 821. (Refer to page
5-35).
(1)-3 Perform speed feed foward control and
model adaptive speed control.
(2) Change the acceleration/deceleration time
to an optimum value.
(1) Decrease Pr. 72 "PWM frequency selec-
tion".
(2) Increase Pr. 820 "Speed control P gain 1".
5 - 39