# Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual Page 517

Fr-a800 series.

 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.
 Changing the motor constants (when setting the Pr.92 and Pr.93 motor
constants in units of mH)
• Set Pr.71 as follows.
Mitsubishi Electric standard motor
Mitsubishi Electric high-efficiency motor
Mitsubishi Electric constant-torque motor
Mitsubishi Electric high-performance
energy-saving motor
Vector control dedicated motor
• Use the following formula to find the Pr.94 setting value and set a desired value as the motor constant parameter.
The setting value of Pr.94 = （1 -
R1
I1
I2
R2/S
V
M
Equivalent circuit diagram of the motor
First motor
Second
Pr.
motor Pr.
82
455
90
458
91
459
92
460
93
461
94
462
859
860
298
560
*1
For the FR-A820-03160(55K) or lower and FR-A840-01800(55K) or lower.
*2
For the FR-A820-75K(03800) or higher and FR-A840-75K(02160) or higher.
516
5. PARAMETERS
5.13 (C) Motor constant parameters
Motor
SF-JR
SF-JR 4P 1.5 kW or lower
SF-HR
SF-JRCA 4P
SF-HRCA
SF-PR
SF-V5RU (1500 r/min series)
SF-V5RU (other than the 1500 r/min series) 1
2
M
）×100(％)
L1×L2
R1: Primary resistance
R2: Secondary resistance
I1: Primary leakage inductance
I2: Secondary leakage inductance
M: Excitation inductance
S: Slip
L1= I1+ M: Primary inductance
L2= I2+ M: Secondary inductance
Name
Motor excitation current
Motor constant (R1)
Motor constant (R2)
Motor constant (L1)/d-axis
inductance (Ld)
Motor constant (L2)/q-axis
inductance (Lq)
Motor constant (X)
Torque current/Rated PM motor
current
Frequency search gain
0 (initial value)
20
40
1
50
70
30
Setting range
*1
0 to 500 A, 9999
*2
0 to 3600 A, 9999
*1
0 to 50 Ω, 9999
*2
0 to 400 mΩ, 9999
*1
0 to 50 Ω, 9999
*2
0 to 400 mΩ, 9999
*1
0 to 6000 mH, 9999
*2
0 to 400 mH, 9999
*1
0 to 6000 mH, 9999
*2
0 to 400 mH, 9999
0 to 100%, 9999
*1
0 to 500 A, 9999
*2
0 to 3600 A, 9999
0 to 32767, 9999
Pr.71 setting
Setting
Initial value
increments
*1
0.01 A
*2
0.1 A
*1
0.001 Ω
*2
0.01 mΩ
*1
0.001 Ω
*2
0.01 mΩ
*1
0.1 mH
*2
9999
0.01 mH
*1
0.1 mH
*2
0.01 mH
*1
0.1%
*2
0.01%
*1
0.01 A
*2
0.1 A
1