Frequency search gain (Pr. 298), offline auto tuning (Pr. 96)
When automatic restart after instantaneous power failure operation (with frequency search) is
valid at V/f control, perform offline auto tuning. Perform offline auto tuning during V/f control in
the following order to set Pr. 298 "Frequency search gain" automatically. (Refer to page 6-88
during advanced magnetic flux vector control and general-purpose magnetic flux vector con-
Before performing offline auto tuning
Check the following before performing offline auto tuning:
● The inverter is under V/f control.
● A motor should be connected. Note that the motor should be at a stop at a tuning start.
● The motor capacity should be equal to or one rank lower than the inverter capacity.
● The maximum frequency is 120Hz.
● A high-slip motor, high-speed motor and special motor cannot be tuned.
● Even if tuning is performed without motor running (Pr. 96 "Auto tuning setting/status" = 21),
the motor may run slightly. Therefore, fix the motor securely with a mechanical brake, or
before tuning, make sure that there will be no problem in safety if the motor runs (caution is
required especially in vertical lift applications). Note that tuning performance is unaffected
even if the motor runs slightly.
● Offline auto tuning will not be performed properly if it is performed with a surge voltage
suppression filter (FFR-DT) connected between the inverter and motor. Remove it before
● Set "21" in Pr. 96 "Auto tuning setting/status". Tuning is performed without motor running.
According to the motor type and the inverter capacity, it takes approximately 9s until tuning
is completed. (Excitation noise is produced during tuning.)
● Set the rated motor current (initial value is rated inverter current) in Pr. 9 "Electronic thermal
O/L relay". (Refer to section 6.8).
● Set Pr. 71 "Applied motor" according to the motor used.
Mitsubishi standard motor,
Mitsubishi high efficiency motor
Mitsubishi constant-torque motor
Other manufacturer's standard motor
Other manufacturer's constant torque motor
Tab. 6-41: Motor selection
Refer to section 6.8.2, for other settings of Pr. 71.
Operation selection at power failure
SF-JR 4P-1.5kW or less
Others (SF-JRC, etc.)
6 - 157