Mitsubishi Electric FR-A700 Technical Manual page 272

2.10.4 Gain adjustment [Pr. 824, 825, 834, 835]
Although stable operation is available with the initial value, make adjustment when any of such case as unusual motor and
machine vibration noise and overcurrent has occurred.
[Pr. ] Name
824 Torque control P gain 1
825 Torque control integral time 1
834 Torque control P gain 2
835 Torque control integral time 2
(1) Adjustment of current loop proportional
(P) gain
Set the proportional gain for torque control. For
general adjustment, make setting within the range 50
to 200% as a guideline.
Increasing the value improves response to a current
command change and reduces current variation with
disturbance. However, a too large gain will cause
instability, generating harmonic torque pulsation.
(2) Adjustment of current control integral
time
Set the integral time of current control during torque
control.
A small value enhances the torque response level,
but a too small value will cause current fluctuation.
Decreasing the value shortens the time taken to
return to the original torque if current variation with
disturbance occurs.
(3) Use two gains
When you want to change the gain according to
applications, or to switch multiple motors with one
inverter, etc., use [Pr. 834 Torque control P gain 2] and
[Pr. 835 Torque control integral time 2].
[Pr. 834 Torque control P gain 2] and [Pr. 835 Torque
control P gain 2] are valid when the RT signal is ON.
(A700)
Initial Value Setting Range
100% 0 to 200%
5ms 0 to 500ms
0 to 200%
9999
9999
0 to 500ms
9999
9999
(4) Adjustment procedure
306
A700 )
Description
Set the current loop proportional gain.
Set the current loop integral compensation time.
Set the current loop proportional gain when the RT
signal is ON.
Without torque control P gain 2 function
Set the current loop integral compensation time when
the RT signal is ON.
Without torque control integral time 2 function
Make adjustment when any of unusual motor and
machine vibration, noise, current, and overcurrent
occurs.
1) Check the conditions and simultaneously change
the [Pr. 824].
2) If you cannot make proper adjustment, change
the [Pr. 825] value and repeat step 1).
Adjustment Method
Set [Pr. 824] a little lower and [Pr. 825] a little higher. First
lower [Pr. 824] and check the motor for unusual vibration
noise and overcurrent. If the problem still persists,
increase [Pr. 825] .
Decrease the value by 10% until just before
unusual noise and current are improved, and
set about 0.8 to 0.9 of that value.
[Pr. 824]
Note that a too low value will produce current
ripples, causing the motor to generate sound
synchronizing with the cycle of current ripples.
Double the current value until just before an
unusual noise and current does not occur, and
set about 0.8 to 0.9 of that value.
[Pr. 825] Note that taking a too long time will produce
current ripples, causing the motor to generate
sound synchronizing with the cycle of current
ripples.
PARAMETER
,