Vacon Plc
Phone: +358-201 2121
Fax:+358-201 212 205
Service: +358-40-8371 150
E-mail: [email protected]
Page 36
Vacon
Pump and fan control with autochange
6. 2
Switching frequency
Motor noise can be minimized by using high switching frequency. Increasing the
frequency reduces the capacity of the frequency converter. Before changing the
frequency from the factory default 10 kHz (3.6 kHz from 30 kW upwards), check the
allowed capacity from the curves in the figure 5.2-3 of the User's Manual.
6. 3
Field weakening point
6. 4
Voltage at the field weakening point
Field weakening point is the output frequency where the output voltage reaches the
set maximum value (par. 6
.
4). Above that frequency the output voltage remains at
the set maximum value.
Below that frequency output voltage depends on the setting of the U/f curve
parameters 1
.
8, 1
.
9, 6
.
5, 6
.
6 and 6
.
7. See figure 6-18.
When the parameters 1
.
10 and 1
.
11, nominal voltage and nominal frequency of
the motor, are set, also parameters 6
.
3 and 6
.
4 are set automatically to the
corresponding values. If different values for the field weakening point and
the maximum output voltage are required, change these parameters after setting
the parameters 1
.
10 and 1
.
11.
6. 5
U/f curve, middle point frequency
If the programmable U/f curve has been selected with the parameter 1
.
8 this
parameter defines the middle point frequency of the curve. See figure 6-18.
6. 6
U/f curve, middle point voltage
If the programmable U/f curve has been selected with the parameter 1
.
8 this
parameter defines the middle point voltage (% from motor nom. voltage) of the
curve. See figure 6-18.
6. 7
Output voltage at zero frequency
If the programmable U/f curve has been selected with the parameter 1
.
8 this
parameter defines the zero frequency voltage of the curve. See figure 6-18.
Un
Par 6
.
4
Par. 6
.
3
U[V]
f[Hz]
UD009K08
Par. 6
.
5
(Olet. 5 Hz)
Par. 6
.
6
(Olet. 10%)
Par. 6
.
7
(Olet. 1.3%)
Figure 6-18 Programmable U/f curve.
