User manual

100 • vacon parameter descriptions
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9
1 = Square:
The voltage of the motor changes following a squared curve form with
the frequency in the area from 0 Hz to the field weakening point where
the field weakening point voltage is also supplied to the motor. The
motor runs under magnetised below the field weakening point and
produces less torque, power losses and electromechanical noise.
Squared U / f ratio can be used in applications where torque demand
of the load is proportional to the square of the speed, e.g. in centrifugal
fans and pumps.
U[V]
f[Hz]
Un
Par. 1.11
Par. 1.14
Par. 1.10
Default: Nominal
voltage of the motor
Linear
Squared
Field weakening
point
Default: Nominal
frequency of the
motor
Figure 9.1: Linear and squared change of motor voltage
2 = Programmable U / f curve:
The U / f curve can be programmed with three different points. Pro-
grammable U / f curve can be used if the other settings do not satisfy
the needs of the application.