Fuji Electric FRENIC-MEGA - Auto Energy Saving Operation (H67); Auto Torque Boost; Manual Torque Boost (F09); Torque Boost

5-56
F codes
E codes
C codes
P codes
H codes
A codes
b codes
r codes
J codes
d codes
U codes
y codes
Chap. 5 FUNCTION CODES
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)
• Manual torque boost (F09)
In torque boost using F09, constant voltage is added to the basic V/f pattern, regardless of the load. To secure a
sufficient starting torque, manually adjust the output voltage to optimally match the motor and its load by using F09.
Specify an appropriate level that guarantees smooth start-up and yet does not cause over-excitation at no or light load.
Torque boost per F09 ensures high driving stability since the output voltage remains constant regardless of the load
fluctuation.
Specify the F09 data in percentage to the rated voltage at base frequency 1 (F05). At factory shipment, F09 is preset to a
level that assures approx. 100% of starting torque.
• Specifying a high torque boost level will generate a high torque, but may cause overcurrent due to
over-excitation at no load. If you continue to drive the motor, it may overheat. To avoid such a situation,
adjust torque boost to an appropriate level.
• When the non-linear V/f pattern and the torque boost are used together, the torque boost takes effect below
the frequency on the non-linear V/f pattern’s point.
• 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 rate
d
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 migh
t
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.