09/01 AWB8230-1412GB
Voltage/frequency
characteristics and boost
81
Voltage/frequency characteristics and boost
The boost with the V/f characteristic has the effect of boosting the
voltage (and consequently boosting the torque) in the lower
frequency range. The manual boost raises the voltage in the
frequency range from the start frequency (standard setting 0.5 Hz)
to half the base frequency (25 Hz with the standard setting of
50 Hz) in every operating stage (acceleration, normal operation,
deceleration), independently of the motor load. With automatic
boost, in contrast, the voltage is boosted according to the motor
load. A voltage boost may cause a fault message and trip due to
the higher currents involved.
Figure 78: Boost characteristics
Parameter settings:
A41 = 00
A42 = 50
A43 = 10.0
A44 = 00
A45 = 100
[%]
U
f
[Hz]
0
5.0
25.0
50.0
PNU A42 = 50
PNU A43 = 10 %
100
PNU Name Adjustable in
RUN mode
Value Function WE
A41 Boost characteristics – 00 Manual boost 00
01 Automatic boost
A42 Manual boost
percentage
j 0 to 99 % Setting the voltage boost level with manual boost. 11
A43 Maximum boost at 1 %
of the base frequency
j 0 to 50 % Setting the frequency with the highest voltage boost as a percen-
tage of the base frequency.
10.0
A44 Voltage/frequency
characteristic
– You can select a quadratic or a V/f
characteristic for accelerating or
decelerating the motor.
00
00 Linear V/f characteristic (constant torque).
01 Quadratic V/f characteristic (reduced torque)
A45 Output voltage
j 50 to 100 %
of the input
voltage
The output voltage can
be set to 50 to 100 % of
the input voltage.
100
a
b
0
100
[%]
U
f
a Linear
b Quadratic
0
100
50
[%]
U
f
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