P
ARAMETER
DESCRIPTIONS
VACON
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10
3.6 U/F
R
ATIO
The options for this parameter are:
0 = Linear:
Motor voltage changes linearly with the frequency in the constant flux area
from 0 Hz to the field weakening point where nominal voltage is supplied to
the motor.
Linear U/f ratio should be used in constant torque applications. See Figure
9.17.
This default setting should be used if no other adjustment is necessary.
1 = Squared:
Motor voltage changes following a squared curve form with the frequency in
the area from 0 Hz to the field weakening point where nominal voltage is also
supplied to the motor. The motor runs magnetised below the field weakening
point and produces less torque, power losses and electromechanical noise.
The U/f ratio can be used in applications in which load torque is proportional
to squared speed.
Figure 10.1: Linear and motor voltage change
U[V]
f[Hz]
Un
Pa r. 1.11
Pa r. 1.14
Pa r. 1.10
Default: Nominal
voltage of the motor
Linear
Squared
Field weakening
point
Default: Nominal
frequency of the
motor
