Mitsubishi Electric FR-A740-00023 Instruction Manual page 133

Fr-a700 series
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(4) Adjustment procedure
Make adjustment when any of such phenomena as unusual motor and machine vibration/noise/current and
overcurrent has occurred.
1)Check the conditions and simultaneously change the Pr. 824 value.
2)If you cannot make proper adjustment, change the Pr. 825 value and repeat step 1).
Set Pr. 824 a little lower and Pr. 825 a little higher. First lower Pr. 824 and check the motor for unusual vibration/noise and
overcurrent. If the problem still persists, increase Pr. 825 .
Decrease the value 10% by 10% until just before unusual noise and current are improved, and set about 0.8 to 0.9
of that value.
Pr. 824
Note that a too low value will produce current ripples, causing the motor to generate sound synchronizing the cycle
of current ripples.
Increase the current value double by double until just before an unusual noise and current does not occur, and set
about 0.8 to 0.9 of that value.
Pr. 825
Note that taking a too long time will produce current ripples, causing the motor to generate sound synchronizing
the cycle of current ripples.
(5) Troubleshooting (Torque)
Phenomenon
Torque control is not
1
exercised normally.
When the torque
command is small, the
2
motor rotates in the
direction opposite to the
start signal.
Normal torque control
cannot be exercised
3
during acceleration/
deceleration.
The motor vibrates.
Output torque is not linear
4
in response to the torque
command.
♦Parameters referred to♦
Pr. 72 PWM frequency selection
Pr. 178 to Pr. 189 (input terminal function selection)
Pr. 800 Control method selection
Pr. 807 Speed limit selection
C16 to C19 (torque setting voltage (current) bias and gain)
Adjustment Method
Cause
(1) The phase sequence of the
motor or encoder wiring is
wrong.
(2) The Pr. 800 Control method
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.
(When Pr. 807 = "0, 2", the speed
limit may be activated since the
speed limit value changes with the
setting of the acceleration/
deceleration time in Pr. 7 and Pr. 8. )
Insufficient torque.
Refer to page 272
Refer to page 222
Refer to page 87
Refer to page 119
Refer to page 288
Torque control by real sensorless vector
control, vector control
Countermeasures
(1) Check the wiring. (Refer to page 12)
(2) Check the Pr. 800 setting. (Refer to page 87)
(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 C16 Terminal 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 288)
(6) Select magnetic flux observer by setting Pr. 95 Online
auto tuning selection. (Refer to page 191)
Recalibrate C16 Terminal 1 bias command (torque/magnetic
flux) and C17 Terminal 1 bias (torque/magnetic flux). (Refer to
page 288)
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 excitation ratio in Pr. 854 to the initial value.
4
123

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