Toshiba TOSVERT VF-AS1 Instruction Manual page 65

1) Increasing torque automatically according to the load
Set the automatic torque boost = (automatic torque boost+auto-tuning)
Automatic torque boost = detects load current in all speed ranges and automatically adjusts voltage output
from inverter. This gives steady torque for stable runs.
Note 1: The same characteristic can be obtained by setting the V/f control mode selection parameter  to 
Note 2: Setting  to  automatically programs  to .
Note 3: The accuracy of auto-tuning can be increased by specifying  (Base frequency),  (Base frequency
2) When using vector control (increasing starting torque and high-precision operations)
Set the automatic torque boost = (sensorless vector control 1+auto-tuning)
Setting automatic torque boost = (Sensorless vector control 1+auto-tuning) provides high starting torque
bringing out the maximum in motor characteristics from the low-speed range. This suppresses changes in motor
speed caused by fluctuations in load to provide high precision operation. This setting is most suitable for transfer and
lifting systems that are operated in speed control mode.
Note 1: The same characteristic can be obtained by setting the V/f control mode selection parameter  to 
Note 2: Setting  to  automatically programs  to .
5
If vector control cannot be programmed....
First read the precautions about vector control in 5.10, 9).
1) If the desired torque cannot be obtained
2) If auto-tuning error "" appears
 (automatic torque boost) and  (V/f control mode selection)
Automatic torque boost is the parameter for setting V/F control mode selection () and auto-tuning ()
together. That is why all parameters related to change automatically when  is changed.
 is always displayed.

Automatic torque boost+auto-tuning

Sensorless vector control 1+auto-tuning

3) Increasing torque manually (V/f constant control)
The VF-AS1 inverter is set to this control mode by factory default.
This is the setting of constant torque characteristics that are suited for such things as conveyors. It can also be used
to manually increase starting torque.
To return to V/f constant control after changing the  setting:
Set the V/f control mode selection parameter = (constant torque characteristic).
Note:If you want to increase torque further, raise the setting value of manual torque boost .
(automatic torque boost) and  (auto-tuning) to .
voltage),  (Motor rated capacity),  (Motor rated current), and  (Motor rated
rotational speed) indicated in the motor name plate.
(Sensorless vector control 1) and  (Auto-tuning) to .

How to set manual torque boost parameter 
⇒ Refer to Section 6.22.
⇒ Refer to Section 6.22.
⇒ Refer to 6.22 selection 3.
⇒ Refer to 6.22 selection 3.
Automatically programmed parameters

Check the programmed value
of . (If  is not
–
changed, it becomes  (V/F
constant).)
Automatic torque boost

Sensorless vector control 1

E-4
E6581301

–
Executed ( after
execution)
Executed ( after
execution)
⇒ Refer to Section 5.6.
⇒ Refer to Section 5.7.