User Guide

Honeywell Parameter Descriptions 59
10
1.10 FIELD WEAKENING POINT
The field weakening point is the output frequency at which the output voltage
reaches the value set with par. 1.11.
1.11 VOLTAGE AT FIELD WEAKENING POINT
Above the frequency at the field weakening point, the output voltage remains
at the value set with this parameter. Below the frequency at the field weaken-
ing point, the output voltage depends on the setting of the U/f curve parame-
ters. See parameters 1.9 - 1.14 and Figures 10.1 and 10.2.
When the parameters 1.1 and 1.2 (nominal voltage and nominal frequency of
the motor) are set, the parameters 1.10 and 1.11 are automatically given the
corresponding values. If you need different values for the field weakening point
and the voltage, change these parameters after setting the parameters 1.1
and 1.2.
1.12 U/F CURVE, MIDDLE POINT FREQUENCY
If the programmable U/f curve has been selected with the parameter 1.9, this
parameter defines the middle point frequency of the curve. See Figure 10.2.
1.13 U/F CURVE, MIDDLE POINT VOLTAGE
If the programmable U/f curve has been selected with the parameter 1.9, this
parameter defines the middle point voltage of the curve. See Figure 10.2.
1.14 OUTPUT VOLTAGE AT ZERO FREQUENCY
This parameter defines the zero frequency voltage of the curve. See Figures
10.1 and 10.2.
1.15 TORQUE BOOST
The voltage to the motor changes automatically with high load torque which
makes the motor produce sufficient torque to start and run at low frequencies.
The voltage increase depends on the motor type and power. Automatic torque
boost can be used in applications with high load torque, e.g. in conveyors.
0 = Disabled
1 = Enabled
Note: In high torque - low speed applications - it is likely that the motor will
overheat. If the motor has to run a prolonged time under these conditions, spe-
cial attention must be paid to cooling the motor. Use external cooling for the
motor if the temperature tends to rise too high.
1.16 SWITCHING FREQUENCY
Motor noise can be minimised using a high switching frequency. Increasing
the switching frequency reduces the capacity of the frequency converter unit.