Hitachi WJ C1 Series User Manual

Chapter 9 Inverter Functions
9-5-5
9.5.3 Using Torque Boost Function
 What should be done when motor rotation is slow to start after the start of operation?
 What should be done if there is insufficient low-speed torque.
 V/f control does not apply any special corrections for motor control. Therefore, when the output
voltage is low, the voltage decreases due to the resistance component and wiring inside the
motor, which reduces the voltage flowing to the motor. The torque boost function compensates
for this drop in voltage to counter the reduction in torque at low-speeds.
 There are two torque boost functions: manual torque boost and automatic torque boost.
 The manual/automatic torque boost functions are available when the "Control mode selection
[A044]
*1
" is set to "[V/f] Fixed torque characteristics (IM) (00)" or "[V/f] Reducing torque
characteristics (IM) (01)".
 Take care to avoid overexciting the motor when increasing the manual torque boost setting.
Boosting the torque increases the flow of current and may cause motor burnout.
Setting the manual torque boost function
 For the manual torque boost function, set the "Manual torque boost value [A042]
*1
" and "Manual
torque boost peak speed [A043]
*1
" to add voltage during V/f control, as shown in the figure
below. Set the values as a percentage of the "Base frequency [A003]
*1
" and "Motor rated voltage
[A082]
*1
", respectively.
Code
Item
Description
Data
[A041]
*1
Torque boost mode
selection
Applies the manual torque boost.
00
[A042]
*1
Manual torque boost
value
Sets the amount of boost at the manual torque
boost break point. Set the value as a
percentage of the " Motor rated voltage
[A082]
*1
".
0.0 to 20.0 (%)
[A043]
*1
Manual torque boost
peak speed
Sets the manual torque boost break point (the
point at which the maximum voltage is added).
Set the value as a percentage of the "Base
frequency [A003]
*1
".
0.0 to 50.0 (%)
*1. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
Manual torque boost peak speed [A043]
*1
Output frequency (%)
Base frequency [A003]
(100%)
Manual torque boost
value [A042]
*1
Motor rated voltage [A082]
(100%)
Output voltage (%)
0
Q
A
A
!

Hitachi WJ C1 Series Specifications

General

Brand	Hitachi
Model	WJ C1 Series
Category	Inverter
Language	English