EM15 User’s Manual
5. Description of Function Codes
95
The V/F control mode is applicable to low requirement load applications (fan or pump) or applications where one
frequency inverter operates multiple motors or there is a large difference between the frequency inverter power
and the motor power.
d2-00
V/F curve setting
Default
0
Setting
Range
0
Linear V/F
1
Multi-point V/F
2
Square V/F
3
1.2-power V/F
4
1.4-power V/F
6
1.6-power V/F
8
1.8-power V/F
10
V/F complete separation
11
V/F half separation
0: Linear V/F
It is applicable to common constant torque load.
1: Multi-point V/F
It is applicable to special load such as dehydrator and centrifuge. Any relationship V/F curve can be obtained by
setting parameters of d2-03 ~ d2-08.
2: Square V/F
It is applicable to centrifugal loads such as fan and pump.
3 ~ 8: V/F curve between linear V/F and square V/F
10: V/F complete separation
In this mode, the output frequency and output voltage of the frequency inverter are independent. The output
frequency is determined by the frequency source, and the output voltage is determined by "Voltage source for V/F
separation" (d2-12).
It is applicable to induction heating, inverse power supply and torque motor control.
11: V/F half separation
In this mode, V and F are proportional and the proportional relationship can be set in d2-12. The relationship
between V and F are also related to the “rated motor voltage” and “rated motor frequency”.
Assume that the voltage source input is X (0% ~100%), the relationship between V and F is:
V/F =
2
×
X
× (Rated motor voltage)/ (Rated motor frequency)
d2-01
Torque boost
Default
Model dependent
Setting Range
0.0% ( torque auto-boost)
0.1%~30.0%
d2-02
Cut-off frequency of torque boost
Default
50.0%
Setting Range
0.0%~80.0%
Actual cut-off frequency= Motor rated frequency*d2-02
To compensate the low frequency torque characteristics of V/F control, you can boost the output voltage of the
frequency inverter at low frequency by modifying d2-01.
If the torque boost is set to too large, the motor is easily overheated, and the frequency inverter easily suffers over
current.
If the load is large and the motor startup torque is insufficient, increase the value of d2-01. If the load is small,
decrease the value of d2-01. If it is set to 0.0, the frequency inverter performs automatic torque boost. In this case,
the frequency inverter automatically calculates the torque boost value based on motor parameters including the
stator resistance.
d2-02 specifies the frequency under which torque boost is valid. Torque boost becomes invalid when this
