BONFIGLIOLI active cube 201

202
Operating Instructions ACU
12/16
17 V/f characteristic
The sensorless control in configurations 110 and 111 is based on the proportional change of output
voltage compared to the output frequency according to the configured characteristic.
By setting the V/f-characteristic, the voltage of the connected 3-phase motor is controlled according
to the frequency. The torque to be applied by the motor at the corresponding operating point
demands the control of the output voltage proportional to the frequency. At a constant output
voltage / output frequency ratio of the frequency inverter, the magnetization is constant in the
nominal operating range of the 3-phase motor. The rating point of the motor or end point of the V/f-
characteristic is set via the guided commissioning with parameter Cut-Off Voltage 603 and
parameter Cut-Off Frequency 604.
The lower frequency range, where an increased voltage is necessary for the start of the drive, is
critical. The voltage at output frequency = zero is set with the parameter Starting Voltage 600. A
voltage increase deviating from the linear course of the V/f characteristic can be defined by
parameters Voltage Rise 601 and Rise Frequency 602. The parameter value percentage is
calculated from the linear V/f characteristic. Via parameters Minimum Frequency 418 and Maximum
Frequency 419, the working range and/or V/f characteristic are defined.
603 (UC)
601 (UK)
600 (US)
U
418 (FMIN)
419 (FMAX)
602 (FK)
604 (FC) f
Working range
(FMIN): Minimum Frequency 418, (FMAX): Maximum Frequency 419,
(US): Starting Voltage 600,
(UK): Voltage Rise 601, (FK): Rise Frequency 602
(UC): Cut-Off Voltage 603, (FC): Cut-Off Frequency 604
Parameter
Setting
No.
Description
Min.
Max.
Factory setting
600
Starting voltage
0.0 V
100.0 V
5.0 V
601
Voltage rise
-100 %
200 %
10 %
602
Rise frequency
0 %
100 %
20 %
603
Cut-off voltage
60.0 V
560.0 V
400.0 V
604
Cut-off frequency
0.00 Hz
599.00 Hz
50.00 Hz
The guided commissioning takes the parameterized rated motor values and reference
data of the frequency inverter into account when it comes to pre-setting the V/f-
characteristic. In the case of asynchronous machines, the speed can be increased at a
constant torque if the motor winding can be switched over from star to delta
connection. If the data for delta connection indicated on the rating plate of the three-
phase motor were entered, the cut-off frequency is increased automatically by the
square root of three.