Mitsubishi Electric 800 Series Instruction Manual page 313

NOTE
• The motor constants measured once during offline auto tuning are stored as parameters and their data are held until offline
auto tuning is performed again. However, the tuning data is cleared when performing All parameter clear.
• Changing Pr.71 after tuning completion will change the motor constant. For example, if the Pr.71 setting is changed to "8093"
after tuned with Pr.71 = "8090", the tuning data become invalid. To use the tuned data, set "8090" again in Pr.71.
• If offline auto tuning has ended in error (see the following table), motor constants are not set.
Perform an inverter reset and perform tuning again.
Error display
8 Forced end
9 Inverter protective function operation
92 The converter output voltage fell to 75% of the rated voltage.
Calculation error.
93
The motor is not connected.
• When tuning is ended forcibly by pressing the STOP/RESET key or turning OFF the start signal (STF or STR) during
tuning, offline tuning does not end properly. (The motor constants have not been set.)
Perform an inverter reset and perform tuning again.
NOTE
• An instantaneous power failure occurring during tuning will result in a tuning error.
After power is restored, the inverter starts normal operation. Therefore, when the STF (STR) signal is ON, the motor starts
forward (reverse) rotation.
• Any fault occurring during tuning is handled as in the normal operation. However, if the retry function is set, no retry is
performed even when a protective function that performs a retry is activated.
• The set frequency monitor displayed during the offline auto tuning is 0 Hz.
CAUTION
• Note that the motor may start running suddenly.
 Parameters updated by tuning results after tuning
First Second
motor Pr. motor Pr.
90 458
92 460
93 461
711 739
712 740
717 741
721 742
859 860
96 463
 Tuning adjustment (Pr.1002)
• The overcurrent protective function may be activated during Lq tuning for an easily magnetically saturated motor (motor
with a large Lq decay ratio). In such case, adjust the target flowing current used for tuning with Pr.1002 Lq tuning target
current adjustment coefficient.
 Changing the motor constants
• The motor constants can be set directly when the motor constants are known in advance, or by using the data measured
during offline auto tuning.
• According to the Pr.71 (Pr.450) setting, the range of the motor constant parameter setting values and units can be
changed. The changed settings are stored in the EEPROM as the motor constant parameters.
312
13. (C) Motor Constant Parameters
13.3 Offline auto tuning for a PM motor (motor constant tuning)
Error cause
Name
Motor constant (R1)
Motor constant (L1)/d-axis inductance (Ld)
Motor constant (L2)/q-axis inductance (Lq)
Motor Ld decay ratio
Motor Lq decay ratio
Starting resistance tuning compensation coefficient 1
Starting magnetic pole position detection pulse width
Torque current/Rated PM motor current
Auto tuning setting/status
Countermeasures
Set "1" in Pr.96 (Pr.463) and retry.
Make the setting again.
Check for the power supply voltage fluctuation.
Check the Pr.83 Rated motor voltage setting.
Check the motor wiring and make the setting again.
Description
Resistance per phase
d-axis inductance
q-axis inductance
d-axis inductance decay ratio
q-axis inductance decay ratio
When the setting value is 10000 or more: With polarity
inversion for compensation, voltage pulse (Pr. setting
minus 10000) μs