Efficient Networks Siemens Sinamics S120 User Manual

Page 141

Vector control

4.12 Motor data identification and rotating measurement

Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4

141

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Figure 4-18 Equivalent circuit diagram for induction motor and cable

If an output filter (see p0230) or series inductance (p0353) is used, the data for this must

also be entered before the standstill measurement is carried out.
The inductance value is then subtracted from the total measured value of the leakage. With

sinusoidal filters, only the stator resistance, valve threshold voltage, and valve interlocking

time are measured.

Note
With diffusion of more than 35% to 40% of the motor nominal impedance, the dynamic

response of the speed and current control is restricted to the area of the voltage limit and to

field weakening mode.

Note
The standstill measurement must be carried out when the motor is cold. In p0625, enter the

estimated ambient temperature of the motor during the measurement (with KTY sensor: set

p0600, p0601 and read r0035). This is the reference point for the thermal motor model and

thermal R

adaptation.

In addition to the equivalent circuit diagram data, motor data identification (p1910 = 3) can

be used for induction motors to determine the magnetization characteristic of the motor. Due

to the higher accuracy, the magnetization characteristic should, if possible, be determined

during the rotating measurement (without encoder: p1960 = 1, 3; with encoder: p1960 = 2,

4). If the drive is operated in the field-weakening range, this characteristic should be

determined for vector control in particular. The magnetization characteristic can be used to

calculate the field-generating current in the field-weakening range more accurately, thereby

increasing torque accuracy.

Note
In comparison with the standstill measurement (p1910), for induction motors, the rotating

measurement (p1960) allows the rated magnetization current and saturation characteristic to

be determined more accurately.