Linear And Quadratic Voltage/Frequency Characteristic - Siemens SIMATIC EM 148-FC Manual

Control mode
This parameter determines the relationship between the frequency output by the
frequency converter and the voltage.
S Linear voltage/frequency characteristic:
Linear voltage rise from the minimum voltage when f = 0 to the rated voltage at
the rated frequency of the motor.
This adjustment ensures an almost constant torque until the rated operating
speed is reached.
S Quadratic voltage/frequency characteristic:
A slow increase in voltage at the start and therefore reduced torque.
This adjustment is particularly suitable for machines such as rotary pumps or
fans, since these have a perfect squared torque/frequency curve.
Figure 4-1
EM 148-FC Frequency Converter
A5E00065321-03
A
U
N
0

Linear and quadratic voltage/frequency characteristic

Functions and Technical Specifications
f
N
f
4-11