Hitachi WJ Series User Manual page 197

Chapter 9
Adjustments when using sensorless vector control
!
 If the desired characteristics cannot be obtained, first execute auto-tuning to set the motor
constant. Then, apply adjustments referring to the table below.
 Before adjusting the "Async. Motor speed response [H005]
[H024]/[H034]
the moment of inertia of the motor.
 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 
Shocks occur at startup.
Rotation momentarily occurs
in the reverse direction to
the specified direction of
rotation at startup, or during
low-speed operation.
Rotation is unstable and
uneven when operating at
low speeds.
Hunting occurs in the motor.
The rotation frequency
decreases when a load
(power running) is applied to
the motor in the stop
direction.
The rotation frequency
increases when a load
(power running) is applied to
the motor in the stop
direction.
The rotation frequency
increases when a load
(regenerative running) is
applied to the motor in the
direction of rotation during
low-speed operation (at
several Hz).
*1. "2nd-motor control [SET]" target parameter. The second control parameter is also subject to setting.
" to the sum of the moment of inertia of the load applied to the motor shaft and
*1
Probable cause 
The speed response of
the control system is
too high.
The result of the motor
control causes a reverse
rotation command to be
momentarily issued.
The speed response of
the control system is
too low.
The speed response of
the control system is
too high.
The motor constant R2
has been set too low.
The motor constant R2
has been set too high.
Regenerative torque is
insufficient for low-
speed operation.
", set the "Async. Motor constant J
*1
Decrease the "Async. Motor speed response
*1
[H005] " in 5% increments.
Decrease the "Async. Motor constant J [H024]/
*1
[H034] " in 5% increments.
Enable "Direction reversal protection selection
[b046]".
Increase the "Async. Motor speed response
[H005] *1 " in 5% increments.
Increase the "Async. Motor constant J [H024]
*1
/[H034]
Decrease the "Async. Motor speed response
*1
[H005] " in 5% increments.
Decrease the "Async. Motor constant J [H024]
*1
/[H034]
Increase the "Async. Motor constant R2 [H021]
/[H031] *1
the set value.
Decrease the "Async. Motor constant R2
[H021]/ [H031]
times the set value.
Increase the "Async. Motor constant R1 [H020]
*1
/[H030]
the set value.
Increase the "Async. Motor constant I0 [H023]
*1
/[H033]
the set value.
9-5-13
Inverter Functions
Example of countermeasures
" in 5% increments.
" in 5% increments.
" in 5% increments up to 1.2 times
*1 " in 5% increments down to 0.8
" in 5% increments up to 1.2 times
" in 5% increments up to 1.2 times