Mitsubishi Electric 800 Series Instruction Manual page 429

(C) Motor constant parameters
POINT POINT
• The function is enabled under Advanced magnetic flux vector control, Real sensorless vector control, and vector control.
• When an induction motor by other manufacturers is used or the wiring length between the inverter and the motor is long (30
m or longer as a reference), use the offline auto tuning function to drive the motor in the optimum operation characteristic.
• Tuning is enabled even when a load is connected to the motor.
• During offline auto tuning, the motor rotation can be locked (Pr.96 = "1") or unlocked (Pr.96 = "101"). The tuning is more
accurate when the motor can rotate (unlocked).
• Reading/writing of the motor constants tuned by offline auto tuning are enabled. The offline auto tuning data (motor
constants) can be copied to another inverter with the operation panel.
• The offline auto tuning status can be monitored with the operation panel and the parameter unit.
Before performing offline auto tuning
Check the following points before performing offline auto tuning:
• A value other than "9999" is set in Pr.80 and Pr.81, and Advanced magnetic flux vector control, Real sensorless vector
control or vector control is selected (with Pr.800).
• A motor is connected. (The motor should not be rotated by the force applied from outside during the tuning.)
• For the motor capacity, the rated motor current should be equal to or less than the inverter rated current. (It must be 0.4 kW
or higher.) If a motor with substantially low rated current compared with the inverter rated current is used, speed and torque
accuracies may deteriorate due to torque ripples, etc. Set the rated motor current to about 40% or higher of the inverter
rated current.
• The target motor is other than a high-slip motor, a high-speed motor, or a special motor.
• The highest frequency is 400 Hz.
• The motor may rotate slightly even if the offline auto tuning without motor rotation (Pr.96 Auto tuning setting/status = "1")
is selected. (The slight motor rotation does not affect the tuning performance.) Fix the motor securely with a mechanical
brake, or before tuning, make sure that it is safe even if the motor rotates. (Caution is required especially in vertical lift
applications.)
• Check the following points for the offline auto tuning with motor rotation (Pr.96 Auto tuning setting/status = "101").
Torque is not sufficient during tuning.
The motor can be rotated up to the speed close to the rated speed.
The mechanical brake is released.
• Make sure to connect the encoder to the motor without coaxial misalignment during vector control. Set the speed ratio to
1:1.
428
PARAMETERS