4-65
F42
Drive Control Selection 1
H68 (Slip Compensation 1 (Operating conditions))
F42 specifies the motor drive control.
Data for
F42
Drive control
Basic control
Speed
feedback
Speed control
0
V/f control with slip compensation inactive
V/f
control
Disable
Frequency control
1
Dynamic torque control
(with slip compensation and auto torque
boost)
Frequency control
with slip
compensation
5
Vector control without speed sensor
Vector
control
Estimated
speed
Speed control
with automatic speed
regulator (ASR)
6
Vector control with speed sensor
Enable
V/f control with slip compensation inactive
Under this control, the inverter controls a motor with the voltage and frequency according to the V/f pattern
specified by function codes. This control disables all automatically controlled features such as the slip
compensation, so no unpredictable output fluctuation occurs, enabling stable operation with constant output
frequency.
Note:
To active slip compensation, refer to P09~P11 as below. Applying any load to an induction motor causes a
rotational slip due to the motor characteristics, decreasing the motor rotation. The inverter’s slip compensation
function prevents the motor from decreasing the rotation due to the slip. That is, this function is effective for
improving the motor speed control accuracy.
Function code
Operation
P12
Rated slip frequency
Specify the rated slip frequency.
P09
Slip compensation gain for driving
Adjust the slip compensation amount for driving.
Slip compensation amount for driving =
Rated slip x Slip compensation gain for driving
P11
Slip compensation gain for braking
Adjust the slip compensation amount for braking.
Slip compensation amount for braking =
Rated slip x Slip compensation gain for braking
P10
Slip compensation response time
Specify the slip compensation response time.
Basically, there is no need to modify the default setting.
To improve the accuracy of slip compensation, perform auto-tuning.
H68 enables or disables the slip compensation function according to the motor driving conditions.
Data for H68
Motor driving conditions
Motor driving frequency zone
Accel/Decel
Constant speed
Base frequency or
below
Above the base
frequency
0
Enable
Enable
Enable
Enable
1
Disable
Enable
Enable
Enable
2
Enable
Enable
Enable
Disable
3
Disable
Enable
Enable
Disable
Dynamic torque control
To get the maximal torque out of a motor, this control calculates the motor torque matched to the load applied and
uses it to optimize the voltage and current vector output.
Selecting this control automatically enables the auto torque boost and slip compensation function so that it is
effective for improving the system response to external disturbances such as load fluctuation, and the motor
speed control accuracy.
Note that the inverter may not respond to a rapid load fluctuation since this control is an open-loop V/f control that
does not perform current control, unlike vector control. One advantage of this control is that the maximum torque
per output current is larger than that of vector control.
