STEP ET Series - P21 Group Advanced Parameters

Chapter 7 Parameter Explanation
Shanghai Sigriner STEP Electric Co., Ltd.
- 98 -
P20.23
Phase sequence of motor 2
0~1
1
P20.24
No-load current coefficient of
motor 2 (%)
1.00~100.00
30.00
Descriptions of the parameters P20.14 - P20.26 of motor 2 are the same as that of motor 1.
7.4.2 P21 group Advanced parameters
Function code
Name
Setting range
Factory setting
P21.01
Stator resistance of motor 1 (Ω)
0.000~65.000
0.100
P21.02
Rotor resistance of motor 1 (Ω)
0.000~65.000
0.441
P21.03
Stator inductance of motor 1 (H)
0.0000~6.5000
0.1028
P21.04
Rotor inductance of motor 1 (H)
0.0000~6.5000
0.1028
P21.05
Mutual inductance (H)
0.0000~6.5000
0.0991
L1-Lm L2-Lm
Rm
Xm
1-S
S
I1
U1
I0
I2
R1 R2
R2
Figure 7-14 Steady-state Equivalent Circuit Diagram of Asynchronous Motor
R
1
, R
2
, L
1
, L
2
, L
m
, I
0
in the figure represent stator resistance, stator inductance, rotor resistance, rotor
inductance, mutual inductance, and excitation current, respectively. The excitation current can be
calculated based on the rated motor current, motor power factor, or measured based on the rotation
auto-tuning.
The relationship between rated torque current, excitation current and rated motor current:
Rated torque current = power factor

motor rated current
No-load excitation current =


 ;
generally, the motor efficiency is approximately 85.
The five parameters, P21.01, P21.02, P21.03, P21.04 and P21.05, are only valid for asynchronous
motors, which are internal characteristic parameters of the motor, and automatically obtained by the
inverter during the motor self-learning process.
The key motor parameters that affect the operation control of the inverter are determined by
performing parameter auto-tuning. After the parameter auto-tuning process is completed, these
motor parameters will be automatically saved in the inverter until the next parameter input or a new
parameter auto-tuning.
The process of parameter auto-tuning is shown as follows:
1 Input P20.00 - P20.11 correctly according to the motor nameplate; set the basic running
frequency P40.01, maximum output frequency P70.02 and maximum output voltage
P70.03 correctly; set the appropriate acceleration and deceleration times P40.02 and
P40.03;
2 Select the execution method of parameter auto-tuning (see starting menu option).