Mitsubishi Electric FR-A700 Technical Manual page 273

2.10.5 Troubleshooting (torque control)
Case
Torque control is not
1
exercised normally.
When the torque command
is small, the motor rotates
2
in the direction opposite to
the start signal.
Normal torque control
cannot be exercised during
3
acceleration/deceleration.
The motor vibrates.
Output torque is not linear
4 in response to the torque
command.
A700
(A700)
Cause
1)The phase sequence of the motor
or encoder wiring is wrong.
(2) The [Pr. 800 Control mode selection]
setting is improper.
(3)The speed limit value is not input.
(4) The torque command varies.
(5)The torque command does not
match the inverter-recognized
value.
(6)Torque variation due to the change in
the motor temperature.
The offset calibration of the torque
command does not match.
The speed limit is activated.
(Since the speed limit value changes
with the setting of the acceleration/
deceleration time [Pr. 7, Pr. 8] , the
speed limit may be activated.)
Insufficient torque.
307
Countermeasures
1) Check the wiring (Refer to page 86)
(2)Check the [Pr. 800] setting. (Refer to page 252)
(3)Set the speed limit value. (If the speed limit value is not
input, the motor will not rotate since the speed limit value is
regarded as 0Hz.)
(4)-1 Check that the command device gives a correct torque
command.
(4)-2 Decrease [Pr. 72 PWM frequency selection].
(4)-3 Increase [Pr. 826 Torque setting filter 1].
(5) Recalibrate [C16Terminal 1 bias command (torque/magnetic
flux) , [C17 Terminal 1 bias (torque/magnetic flux), [C18
Terminal 1 gain command (torque/magnetic flux) , [C19
Terminal 1 gain (torque/magnetic flux) . (Refer to page 320)
(6)Select magnetic flux observer by setting [Pr. 95 Online auto
tuning selection] . (Refer to page 276)
Recalibrate [C16 Terminal 1bias command (torque/magnetic flux)]
and [C17 Terminal 1bias (torque/magnetic flux) .] (Refer to page
320)
Reduce the acceleration/deceleration time.
Or, set the acceleration/deceleration time to "0". (The speed
limit during acceleration/deceleration depends on the speed
limit during the constant speed.)
Return the [Pr. 854 Excitation ratio] to the initial value.
PARAMETER
2