Selecting The U/F Characteristic - Siemens SINAMICS G120 Operating Instructions Manual

Setting functions
8.5 Motor control
The inverter increases its output voltage – also above the motor rated speed up to the
maximum output voltage. The higher the line voltage, the greater the maximum inverter
output voltage.
If the inverter has reached its maximum output voltage, then it can only increase its output
frequency. From this point onwards, the motor is operated in field weakening; this means
that the available torque linearly decreases with increasing speed.
The value of the motor voltage at the rated motor frequency also depends on the following
variables:
● Ratio between the inverter size and the motor size
● Line voltage
● Line impedance
● Actual motor torque
The maximum possible motor voltage as a function of the input voltage is provided in the
technical data, also see Section Technical data (Page 385).
8.5.1.2

Selecting the U/f characteristic

Procedure
Proceed as follows to select a U/f characteristic using STARTER:
1. Go online.
2. Select the U/f characteristic curve in one of the screen forms "speed controller" or "U/f
control".
You have selected a U/f characteristic.
Proceed as follows to select a U/f characteristic using BOP-2:
1. Go into the menu "PARAMS".
2. As parameter filter, select "EXPERT".
3. Set p1300 to the appropriate value.
You have selected a U/f characteristic.
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Converter with the CU250S-2 Control Unit (vector)
Operating Instructions, 06/2013, FW V4.6, A5E31759476B AB