Siemens SINAMICS G120XA - U;F Characteristics of the Converter

Function description
The converter has different U/f characteristics.
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① The voltage boost of the characteristic optimizes motor start-up
② With flux current control (FCC), the converter compensates the voltage drop across the stator re‐
sistance of the motor
Figure 6-56 U/f characteristics of the converter
With increasing speed or output frequency, the converter increases its output voltage U. The
maximum possible output voltage of the converter depends on the line voltage.
The converter can increase the output frequency even at the maximum output voltage. The
motor is then operated with field weakening.
The value of the output voltage at the rated motor frequency also depends on the following
variables:
The value of the output voltage at the rated motor frequency p0310 also depends on the
following variables:
● Ratio between the converter size and the motor size
● Line voltage
● Line impedance
● Actual motor torque
The maximum possible output voltage as a function of the input voltage is stated in the technical
data.
Advanced commissioning
6.6 Motor control
SINAMICS G120XA converter
Operating Instructions, 03/2019, FW V1.0, A5E44751205B AB 275