Vacon 20 SERIES, Applications Manual

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Parameter description vacon • 48
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3
3.9 Motor control
P9.1 F
IELD WEAKENING POINT
Output frequency corresponding to max voltage.
Note: if P1.2 Nominal Frequency is changed, P9.1 will be set at same value.
P9.2 F
IELD WEAKENING POINT VOLTAGE
Motor voltage when frequency is above FWP, defined as % of nominal voltage.
Note : if P1.1 Nominal Voltage is changed, P9.2 will be set at 100%.
P9.3 U/
F SELECTION
0: linear
The voltage of the motor changes linearly as a function of output frequency
from zero frequency voltage P9.6 to the field weakening point (FWP)
voltage P9.2 at FWP frequency P9.1 This default setting should be
used if there is no special need for another setting.
Figure 6. Linear and quadratic curve of the motor voltage.
1: quadratic
(from voltage P9.6 at 0Hz, to voltage P9.2 at P9.1 frequency)
The voltage of the motor changes from zero point voltage P9.6 following a squared curve form
from zero to the field weakening point P9.2. The motor runs under-magnetized below the field
weakening point and produces less torque. Squared U/f ratio can be used in applications where
torque demand is proportional to the square of the speed, e.g. in centrifugal fans and pumps.
U[V]
f[Hz]
Default: Nominal
voltage of the motor
Linear
Squared
Field
weakening
point
Default:
Nominal frequency
of the motor