8-5
When the variable torque V/f pattern is selected (F37 = 0 or 3), the output voltage may be low at a low
frequency zone, resulting in insufficient output torque, depending on the characteristics of the motor and
load. In such a case, it is recommended to increase the output voltage at the low frequency zone using the
non-linear V/f pattern.
Recommended value:
H50 = 1/10 of the base frequency
H51 = 1/10 of the voltage at base frequency
Torque boost: Data setting range: 0.0 to 20.0 (%) (100%/Rated voltage at base frequency)
• Auto torque boost
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
but 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.)
You can 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 change from constant speed operation
may be slow. Do not use this feature for such 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, you may get a little or no energy saving advantage. 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.