Mitsubishi Electric 800 Series Instruction Manual page 524

Offline auto tuning when performing a frequency search by V/F control
(reduced impact restart)
• When the frequency search (reduced impact restart) is selected by setting Pr.162 Automatic restart after instantaneous
power failure selection = "3 or 13", perform offline auto tuning.
Before executing offline auto tuning
Check the following points before performing offline auto tuning:
• V/F control is selected.
• A motor is connected. (The motor should not be rotated by the external force applied from outside during the tuning.)
• The motor with the rated motor current equal to or less than the inverter rated current is used. (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 motor may run slightly without actually turning during offline auto-tuning (Pr.96 Auto tuning setting/status = "11"), so
either firmly secure the motor by the mechanical brake or check to see if turning the motor will cause any safety problems.
(Attention is required for lifts, in particular.) The motor turning slightly will not affect tuning performance.
Setting
1) Set Pr.96 Auto tuning setting/status = "11".
2) Set the rated motor current (initial value is inverted rated current) to Pr.9 Electronic thermal O/L relay. (Refer to
317.)
3) Set Pr.71 Applied motor according to the motor to be used.
Motor
Standard motor
Constant-torque motor
Other manufacturer's standard motor
Other manufacturer's constant-torque motor
Performing tuning
POINT POINT
• Before performing tuning, check the monitor display of the operation panel or the parameter unit if the inverter is in the state
ready for tuning. Turning ON the start command while tuning is unavailable starts the motor.
• In the PU operation mode, press
For External operation, turn ON the start command (STF signal or STR signal). Tuning will start. (At this time, excitation
noise occurs.)
NOTE
• It takes about 10 seconds for tuning to complete. (The time depends on the inverter capacity and motor type.)
• Satisfy the required inverter start conditions to start offline auto tuning. For example, stop the input of MRS signal.
• To force tuning to end, use the MRS or RES signal or press
(Turning the start signal (STF signal or STR signal) OFF also ends tuning.)
• During offline auto tuning, only the following I/O signals are valid. (Initial value)
Input terminals <valid signals> STP (STOP), OH, MRS, RT, RES, STF, and STR
Output terminals: RUN, OL, IPF, FM, AM, and A1B1C1
• When the rotation speed and the output frequency are selected for terminals FM and AM, the progress status of offline auto
tuning is output in fifteen steps from FM and AM.
• During execution of offline auto tuning, do not switch the second function selection signal (RT) ON or OFF. Auto tuning is not
executed properly.
• Since the RUN signal turns ON when tuning is started, caution is required especially when a sequence which releases a
mechanical brake by the RUN signal has been designed
• When executing offline auto tuning, input the run command after switching ON the main circuit power (R/L1, S/L2, T/L3) of
the inverter.
• While Pr.79 Operation mode selection = "7", turn the PU operation external interlock (X12) signal ON to tune in the PU
operation mode.
Pr.71 setting
0 (3, 4)
1 (13, 14)
0 (3, 4)
1 (13, 14)
/ on the operation panel.
(A) Application parameters
on the operation panel.
PARAMETERS
page
5
GROUP
A
523