V/F Curve Diagram - Delta Electronics AC Motor Drive VFD-G User Manual

This parameter is to set V/F curve. If this parameter isn't set to 00, parameter 01-03 and 01-04
will disable.
Input current of the motor could divide into two orthogonal vectors: magnetic vector and torque
vector. Gap flux, which is produced by Magnetic vector, is in direct proportion with output
voltage of motor. Torque vector produces torque. Torque is in direct proportion with the result
of magnetic vector multiply by torque vector. In theory, if the value of magnet vector is the
same with torque vector (in unsaturated flux condition), the input current is minimum. If motor
loading is unsteady torque loading (loading torque is in direct proportion with speed. For
example, the loading of fan or pump), loading torque is low during low speed, suitable lower
input voltage will decrease input current of magnetic field to lower flux loss and iron loss of the
motor and promote whole efficiency.
When this parameter is set to high power V/F curve and low frequency torque is lower, it is not
suitable for AC drive to accel/decel quickly. If it needs to accel/decel quickly, it is not
recommended to use this parameter.
Revision July 2008, EG03, SW V1.06
01-02
Voltage%
100
90
80
70
60 2 power curve
50
3 power curve
40
30
20
10
0 20

V/F Curve Diagram

1.5 power curve
1.7 power curve
60
40
80
Chapter 4 Parameters|
Frequency
%
01-01
100
4-89