Hitachi WJ Series

Chapter 9 Inverter Functions
9-5-6
Setting the automatic torque boost function
 The automatic torque boost function automatically adjusts the output frequency and output
voltage according to load conditions.
 When using the automatic torque booth function, be sure to set the motor constant for your
motor. For details, refer to "8.1.5 Setting Motor Constant" or "8.3 Carrying Out Motor Auto-
tuning".
 Automatic energy-saving operation, multi motor drive, and V/f control with encoder will be
unavailable while using the automatic torque boost function.
Code
Item
Description
Data
[A041]
*1
Torque boost mode
selection
Applies the automatic torque boost.
01
[A046]
*1
Automatic torque boost
voltage compensation gain
Adjusts the output frequency and added
voltage when automatically boosting torque.
0 to 255
[A047]
*1
Automatic torque boost slip
compensation gain
0 to 255
 If an overcurrent trip occurs during deceleration, set "AVR function selection [A081]
*1
" to "Always
enable (00)".
 If the desired characteristics cannot be obtained, adjust each item referring to the table below.
 Overcurrent and other issues may occur if motor rotation is obstructed due to motor locking
from braking or interference from foreign objects. If this cannot be resolved with adjustments,
try checking around the motor's periphery.
 If the "Output frequency monitor [d001]" changes significantly under load, a function that makes
automatic changes to the frequency, such as the overload limit function, non-stop operation
during instantaneous power failure, or the overvoltage suppressor, may have been triggered
under certain function settings. For details, refer to "Chapter 15 Tips/FAQ/Troubleshooting".
Event 
Probable cause 
Example of countermeasures
Slow motor rotation
at low speed
Unable to produce torque
due to insufficient output
voltage.
Increase the "Automatic torque boost voltage
compensation gain [A046]
*1
" in increments of
around 5%.
Reduce the "Carrier frequency [b083]".
Unable to produce torque
due to insufficient frequency
compensation.
Increase the "Automatic torque boost slip
compensation gain [A047]
*1
" in increments of
around 5%.
Reduction in motor
rotation frequency
with heavier loads.
Unable to produce torque
due to insufficient frequency
compensation.
Increase the "Automatic torque boost slip
compensation gain [A047]
*1
" in increments of
around 5%.
Increase in motor
rotation frequency
with heavier loads.
Increase in frequency due to
excessive frequency
compensation.
Decrease the "Automatic torque boost slip
compensation gain [A047]
*1
" in increments of
around 5%.
An overcurrent error
occurs with heavier
loads, or during
acceleration.
Increase in current due to
excessive voltage
compensation.
Decrease the "Automatic torque boost voltage
compensation gain [A046]
*1
" in increments of
around 5%.
Increase in frequency due to
excessive frequency
compensation.
Decrease the "Automatic torque boost slip
compensation gain [A047]
*1
" in increments of
around 5%.
*1. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
A
!