5-2
Setting V/f Control
5-2-1
Motor Control Method (V/f Characteristics)
• V/f control is a method of controlling a motor by setting the output voltage and frequency of the in-
verter as V/f characteristics. This is effective for using the inverter easily.
• Set 0 and 3 at Drive Control Selection and select the V/f characteristics (output voltage and output
frequency).
Parameter No. Function name Data
Default da-
ta
Unit
F42/A14
1st Drive Control
Selection/2nd
Drive Control Se-
lection
*1
0: IM V/f control
3: IM V/f control with speed sensor
0 -
F37/A13
1st V/f Character-
istics
Selection/2nd V/f
Characteristics Se-
lection
0: Variable torque load
1: Constant torque load
1 -
*1. To enable switching to the 1st and 2nd control, allocate “12: SET (2nd control)” to either of input terminal
[DI1] to [DI7].
V/f Control (Induction Motor) (F42/A14 = 0)
V/f control outputs the voltage and frequency according to a preset V/f pattern to operate the motor.
Also, slip compensation function enabled/disabled can be switched by Slip compensation Function Se-
lection (H442). For details on slip compensation, refer to 5-2-3 Slip Compensation on page 5-16.
V/f Control with Speed Sensor (Induction Motor) (F42/A14 = 3)
When a load is applied to an induction motor, slip occurs according to characteristics of the motor and
this results in a drop in motor rotation speed.
With V/f control with speed sensor, the motor rotation speed is detected by an encoder mounted on
the motor shaft, and the slip frequency is compensated by PI control so that the motor rotation speed
matches the speed equivalent to the instructed speed. As a result, the speed control accuracy of the
motor is improved.
Constant Torque Characteristics (F37/A13 = 1)
This setting is suitable for cart, conveyor, overhead traveling crane, and other applications where a tor-
que is required, independent of the motor rotation speed.
It enables the output of a constant torque based on the frequency, according to the V/f characteristics
that represent the proportional relationship between the output frequency and the output voltage.
For the base frequency, set the rated frequency of the motor
.
5 Basic Settings
5-10
M1 Series Standard Type User's Manual (I669)
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