4-58
• Auto torque boost (F37 = 2, 5)
If the auto torque boost is selected, the inverter automatically optimizes the output voltage to fit the motor with its
load. Under light load, the inverter decreases the output voltage to prevent the motor from over-excitation. Under
heavy load, it increases the output voltage to increase the output torque of the motor.
• Since this function relies also on the characteristics of the motor, set the base frequency 1 (F04), the
rated voltage at base frequency 1 (F05), and other pertinent motor parameters (P01 through P03 and
P06 through P99) in line with the motor capacity and characteristics, or else perform auto-tuning (P04).
• When a special motor is driven or the load does not have sufficient rigidity, the maximum torque might
decrease or the motor operation might become unstable. In such cases, do not use auto torque boost
instead choose manual torque boost per F09 (F37 = 0 or 1).
Auto energy saving operation (H67)
If the auto energy saving operation is enabled, the inverter automatically controls the supply voltage to the motor
to minimize the total power loss of motor and inverter. (Note that this feature may not be effective depending upon
the motor or load characteristics. Check the advantage of energy saving before you actually apply this feature to
your machinery.)
Select whether applying this feature to constant speed operation only or applying to constant speed operation and
accelerating/decelerating operation.
Data for H67
Auto energy saving operation
0
Enable only during running at constant speed
1
Enable during running at constant speed or accelerating/decelerating
(Note: For accelerating/decelerating, enable only when the load is light.)
If auto energy saving operation is enabled, the response to a motor speed changes from constant speed operation
may be slow. Do not use this feature for machinery that requires quick acceleration/deceleration.
• Use auto energy saving only where the base frequency is 60 Hz or lower. If the base frequency is set at
60 Hz or higher, little or no energy saving advantage may result. The auto energy saving operation is
designed for use with the frequency lower than the base frequency. If the frequency becomes higher than
the base frequency, the auto energy saving operation will be invalid.
• Since this function relies also on the characteristics of the motor, set the base frequency 1 (F04), the
rated voltage at base frequency 1 (F05), and other pertinent motor parameters (P01 through P03 and
P06 through P99) in line with the motor capacity and characteristics, or else perform auto-tuning (P04).
• Under the vector control without speed sensor, the auto energy saving operation is disabled.
F38, F39
Stop frequency (Detection mode, Holding time)
(Refer to F23.) see page 4-51
F40, F41
Torque Limiter 1-1,
E16, E17 Torque Limiter 2-1, Torque Limiter 2-2
Torque Limiter 1-2
H73 Torque Limiter (Operating conditions)
H76 Torque Limiter (Frequency increment limit for braking)
Under V/f control
If the inverter’s output torque exceeds the specified levels of the torque limiters (F40, F41, E16, E17, and E61 to
E63), the inverter controls the output frequency and limits the output torque to prevent a stall.
To use the torque limiters, it is necessary to configure the function codes listed in the table on the next page.
In braking, the inverter increases the output frequency to limit the output torque. Depending on the
conditions during operation, the output frequency could be excessive. H76 (Frequency increment limit for
braking) is provided to limit the increasing frequency component.