YASKAWA GA700 Series Technical Manual page 937

Adjust this parameter in these conditions:
• If oscillation occurs at the time of start up, increase the setting value.
• If hunting occurs when operating at low speed, increase the setting value.
• If fast changes in the load cause hunting, increase the setting value in 0.1-unit increments. If you cannot stop
hunting, set n8-51 [Pull-in Current @ Acceleration] to 0% and set n8-54 to 0.00 s, and disable compensation
for voltage errors.
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n8-55: Motor to Load Inertia Ratio
No.
Name
(Hex.)
n8-55 Motor to Load Inertia Ratio
(056E)
Sets the ratio between motor inertia and machine inertia to adjust the ACR.
Adjust in the following situations.
• If torque and speed response are unsatisfactory, gradually increase the setting from 0.
• If the motor does not run smoothly, gradually increase the setting from 0.
• If the motor stalls during run at constant speed, gradually increase the setting from 0.
• If there is vibration or hunting, decrease the setting.
Note:
• If the value too low, the drive will detect STPo [Motor Step-Out Detected].
• If you use one motor or more than motor at low inertia and the value is too high, there can be vibration in the motor.
0 : Below 1:10
Use this setting in these conditions:
• The ratio between the motor inertia and machine inertia is less than 1:10
• There are large current ripples
1 : Between 1:10 and 1:30
Use this setting in these conditions:
• The ratio between the motor inertia and machine inertia is approximately 1:10 to 1:30
• Parameter n8-55 = 0 and the drive detects STPo because of an impact load or sudden acceleration/deceleration.
2 : Between 1:30 and 1:50
Use this setting in these conditions:
• The ratio between the motor inertia and machine inertia is approximately 1:30 to 1:50
• Parameter n8-55 = 1 and the drive detects STPo because of an impact load or sudden acceleration/deceleration.
3 : Beyond 1:50
Adjust this parameter in these conditions:
• The ratio between the motor inertia and machine inertia is more than 1:50
• Parameter n8-55 = 2 and the drive detects STPo because of an impact load or sudden acceleration/deceleration.
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n8-57: HFI Overlap Selection
No.
Name
(Hex.)
n8-57 HFI Overlap Selection
(0574)
Note:
• When you set n8-57 = 1, do High Frequency Injection Auto-Tuning.
• When there is high frequency injection, the motor will make an excitation sound.
• When you use Zero Speed Control, set E1-09 = 0.0 [Minimum Output Frequency = 0.0 Hz].
0 : Disabled
Use this setting with SPM motors. The speed control range is approximately 1:20.
When n8-57 = 0, you cannot set E1-09 [Minimum Output Frequency] ≤ 1/20 of the value of E1-06 [Base
Frequency].
1 : Enabled
YASKAWA SIEPC71061705H GA700 Series Technical Manual
V/f CL-V/f OLV CLV AOLV
Sets the ratio between motor inertia and machine inertia.
V/f CL-V/f OLV CLV AOLV
Sets the function that detects motor speed with high frequency injection.
12.10 n: Special Adjustment
Description
OLV/PM AOLV/PM CLV/PM EZOLV OLV/PM
Description
OLV/PM AOLV/PM CLV/PM EZOLV OLV/PM
Default
(Range)
0
(0 - 3)
Default
(Range)
0
(0, 1)
12
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