Hitachi WJ C1 Series

Chapter 9 Inverter Functions
9-5-10
9.5.6 Stabilizing Motor Hunting
 During V/f control, the motor can vibrate and become unstable when exceeding a constant
frequency. How to adjust settings to stabilize the motor?
 Motor rotation becomes unstable. How to adjust settings to stabilize the motor?
 The "Async. Motor stabilization constant [H006]
*1
" is a function that stabilizes the motor when
hunting occurs. Find and adjust the point where hunting subsides within the range of values.
 Refer to the "Probable cause" in the table below when adjusting.
 If the motor is hunting or vibrating, check that the motor capacity, number of motor poles, base
frequency, maximum frequency, and motor rated voltage are set properly. For details, refer to
"8.1.3 Setting the Motor Specification Label Data to Parameters".
 Other ways to inhibit hunting include the following. If these countermeasures do not produce
the desired effect, return the values to their original values.
- Gradually reduce the "Carrier frequency [b083]" to 2 kHz.
- Gradually reduce the "Output voltage gain [A045]
*1
" to 80%.
Code
Item
Description
Data
[H006]
*1
Async. Motor
stabilization constant
Adjust this value if hunting occurs in the
motor.
0 to 255
[A045]
*1
Output voltage gain
Reduce this value if hunting occurs in
the motor. Note the lowering the setting
will reduce the output voltage.
20 to 100 (%)
[b083]
*2
Carrier frequency
Changes the PWM output carrier
frequency. Reduce this if hunting occurs.
2.0 to 15.0 (kHz) (ND)
2.0 to 10.0 (kHz) (LD)
*1. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
*2. Restrictions may apply to the carrier frequency under certain configurations. For details, refer to "9.10
Using System Protection Functions".
Event 
Probable cause 
Example of countermeasures
Hunting occurs
in the motor.
A single inverter is driving multiple
motors.
Set the "Async. Motor stabilization constant
[H006]" to 0%.
The driving load has a large amount
of inertia, such as a fan.
Reduce the "Async. Motor stabilization constant
[H006]" in increments of around 10%.
This may occur when the motor
capacity is larger than the inverter's
rated capacity.
This may occur when the motor
capacity is smaller than the inverter's
rated capacity.
Increase the "Async. Motor stabilization
constant [H006]" in increments of around 10%.
The motor's primary resistance is less
than that of a standard motor.
Q
A
!