Troubleshooting In Torque Control - Mitsubishi Electric FR-A800 Series Instruction Manual

NOTE
• The RT signal is a second function selection signal which also enables other second functions. (Refer to
• The RT signal is assigned to terminal RT in the initial status. Set "3" in one of Pr.178 to Pr.189 (Input terminal function
selection) to assign the RT signal to another terminal.
 Adjustment procedure
Adjust if any of phenomena such as unusual vibration, noise, current or overcurrent is produced by the motor or machinery.
1.
Change the Pr.824 setting while checking the conditions.
2.
If it cannot be adjusted well, change the Pr.825 setting, and perform step 1 again.
Set Pr.824 lower and Pr.825 longer. First, lower Pr.824 and then check of there is still any abnormal vibration, noise or
current from the motor If it still requires improvement, make Pr.825 longer.
Lower the setting by 10% each time and set a value that is approximately 80 to 90% of the setting
Pr.824 immediately before the abnormal noise or current improves.
If set too low, current ripple is produced and produces a sound from the motor that synchronizes with it.
Lengthen the current setting by doubling it each time and set a value that is approximately 80 to 90% of the
Pr.825 setting value, immediately before abnormal noise or current is improved.
If set too long, current ripple is produced and produces a sound from the motor that synchronizes with it.
5.4.7
Sensorless Sensorless Sensorless Vector Vector Vector
Condition
Torque control does not
1
operate properly.
When a small torque
command is given, the
2 motor rotates in a
direction opposite to the
start signal.
Torque control cannot
operate normally during
3 acceleration/
deceleration.
The motor vibrates.
Output torque is
4 nonlinear for the torque
command.
Parameters referred to
Pr.72 PWM frequency
Pr.178 to Pr.189 (Input terminal function
Pr.800 Control method
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Troubleshooting in torque control

Possible cause
• There is incorrect phase sequence
between the motor wiring and
encoder wiring.
• Pr.800 Control method selection
is not appropriate.
• The speed limit value has not been
input.
• Torque command varies.
• The torque command and the torque
recognized by the inverter are
different.
• Torque fluctuation due to motor
temperature variation
• The option to be used and
parameter settings do not match.
• Torque offset calibration is
inaccurate.
• Speed limit is operating.
(Speed limit may operate because
the speed limit value will increase or
decrease according to acceleration/
deceleration time setting of Pr.7 and
Pr.8 when Pr.807 = "0 or 2".)
Torque shortage.
selectionpage 356
selection)page 521
selectionpage 221
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Adjustment method
• Check the wiring. (Refer to
• Check the Pr.800 setting. (Refer to
• Set the speed limit value. (If speed limit value is not input, it
becomes 0 Hz by default and the motor does not run.)
• Check that the torque command sent from the controller is
correct.
• Set Pr.72 PWM frequency selection lower.
• Set Pr.826 Torque setting filter 1 higher.
• Re-calibrate the settings of 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
• Select the magnetic flux observer by Pr.95 Online auto
tuning selection. (Refer to
• Correctly set Pr.862 Encoder option selection according to
the option to be used. (Refer to
• Re-calibrate C16 and C17. (Refer to
• Set the acceleration/deceleration time shorter.
Alternatively, set "0" for the acceleration/deceleration time.
(Forward/reverse rotation speed limit at this time is the value
at a constant speed.)
Return Pr.854 Excitation ratio to the initial value.
5.4 Torque control under Real sensorless vector control and Vector control
page
Countermeasure
page 91.)
page 221.)
page 510.)
page 558.)
page 226.)
page 510.)
5. PARAMETERS
1
525.)
2
3
4
5
6
7
8
9
10
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