Troubleshooting In Torque Control - Mitsubishi Electric 800 Series Instruction Manual

Torque control under Real sensorless vector control and vector control
Using two types of gain (Pr.834, Pr.835)
Torque control P gain 2
• Use Pr.834
according to application or if multiple motors are switched by a single inverter.
• The Pr.834 and Pr.835 settings are valid when the second function selection (RT) signal is ON.
NOTE
• The RT signal is a second function selection signal. The RT signal also enables other second functions. (Refer to
• RT signal is assigned to the terminal RT in the initial status. Set "3" in any 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 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% increments and set a value that is approximately 0.8 to 0.9 times the setting value, immediately
Pr.824 before abnormal noise or current is improved.
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 0.8 to 0.9 times the setting
Pr.825 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

Troubleshooting in torque control

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 nonlinear
4
for 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
Pr.919, Pr.920 (torque setting voltage (current) bias/gain)
202
PARAMETERS
Torque control integral time 2
, Pr.835
Adjustment method
Cause
• There is incorrect phase sequence between
the motor wiring and encoder wiring.
• Pr.800 Control method selection setting
is applied.
• 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
page 261
page 415
page 137
page 195
page 407
if the gain setting needs to be switched
Sensorless Sensorless Sensorless Vector
Countermeasure
• Check the wiring. (Refer to page
• Check the setting of Pr.800. (Refer to
• Set 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 Pr.919 Terminal 1 bias command
(torque), Pr.919 Terminal 1 bias (torque), Pr.920
Terminal 1 gain command (torque), and Pr.920
Terminal 1 gain (torque). (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
141.)
• Re-calibrate Pr.919. (Refer to
• Set the acceleration/deceleration time shorter.
Alternatively, set acceleration/deceleration time to "0".
(Speed limit during acceleration/deceleration is
determined by the speed limit for constant speed.)
Return Pr.854 Excitation ratio to the initial value.
page 419.)
Vector Vector
62.)
page 137.)
page 407.)
page 444.)
page
page 407.)