Command; The Motor Speed Is Not Stable When Using A Pm Motor; There Is Too Much Motor Oscillation And The Rotation Is Irregular; Deceleration Takes Longer Than Expected When Dynamic Braking Is Enabled - YASKAWA GA80U4720ABM Manual

7.10 Troubleshooting Without Fault Display
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The Drive Frequency Reference Is Different than the Controller Frequency
Reference Command
Causes
The analog input gain and bias for the frequency reference input are set
incorrectly.
The drive is receiving frequency bias signals from analog input terminals A1 to
A3 and the sum of all signals makes the frequency reference.
The motor rotates faster than the frequency reference at low speed.
PID control is enabled.
◆

The Motor Speed Is Not Stable When Using a PM Motor

Causes
E5-01 [PM Motor Code Selection] is set incorrectly.
The drive is operating the motor at more than the specified speed control range.
The motor is hunting.
Hunting occurs at start.
Too much current is flowing through the drive.
Operation is not stable when n8-57 = 1 [HFI Overlap Selection = Enabled].
◆

There Is Too Much Motor Oscillation and the Rotation Is Irregular

Causes
Unsatisfactory balance of motor phases.
The motor is hunting.
◆

Deceleration Takes Longer Than Expected When Dynamic Braking Is Enabled

Causes
The stall prevention during deceleration setting is incorrect.
The deceleration time setting is too long.
The motor torque is not sufficient.
366
Examine the gain and bias settings for the analog inputs that set the frequency reference.
• Terminal A1: H3-03 [Terminal A1 Gain Setting], H3-04 [Terminal A1 Bias Setting]
• Terminal A2: H3-11 [Terminal A2 Gain Setting], H3-12 [Terminal A2 Bias Setting]
• Terminal A3: H3-07 [Terminal A3 Gain Setting], H3-08 [Terminal A3 Bias Setting]
• Examine parameters H3-02, H3-10, H3-06 [MFAI Function Select]. If two or more of these
parameters are set to 0, change the settings.
• Use U1-13 to U1-15 [Terminal A1, A2, A3 Input Voltage] to make sure that the analog input
values set to terminals A1, A2, and A3 are applicable.
Reduce the value set in n4-70 [Speed Command Comp @ Low Freq].
If PID control is not necessary, set b5-01 = 0 [PID Mode Setting = Disabled].
Note:
When PID control is enabled, the drive adjusts the output frequency as specified by the target
value. The drive will only accelerate to the maximum output frequency set in E1-04 [Maximum
Output Frequency] while PID control is active.
Refer to "Motor Performance Fine-Tuning" in the technical manual.
Examine the speed control range and adjust the speed.
Adjust these parameters to have the largest effect:
• n8-55 [Motor to Load Inertia Ratio]
• n8-45 [Speed Feedback Detection Gain]
• C4-02 [Torque Compensation Delay Time]
Increase the value set in C2-01 [S-Curve Time @ Start of Accel].
Set E5-01 [PM Motor Code Selection] correctly as specified by the motor. For special-purpose
motors, enter the correct value to E5-xx as specified by the motor test report.
• Do High Frequency Injection Auto-Tuning.
• Decrease the value set in n8-41 [HFI P Gain] in increments of 0.5.
Note:
Set n8-41 > 0.0 for IPM motors.
• Make sure that the drive input power voltage supplies stable power.
• Set L8-05 = 0 [Input Phase Loss Protect Select = Disabled].
• Set n1-01 = 1 [Hunting Prevention Selection = Enabled].
• Increase the value of n2-01 [SpdFeedbackDetectCtr (AFR) Gain] or n2-02 [SpdFeedbackDetCtr
(AFR)TimeConst1].
• Examine the setting for L3-04 [Decel Stall Prevention Selection].
• When the drive has a dynamic braking option installed, set L3-04 = 0 [Disabled].
• If the drive detects ov [Overvoltage], set L3-04 = 3 [General Purpose w/ DB resistor].
Set C1-02, C1-04, C1-06, or C1-08 [Deceleration Times] to applicable values.
Use a larger motor.
Note:
If these items are correct, the demand on the motor is more than the motor capacity:
• Parameter settings are correct.
• The drive does not detect ov [Overvoltage].
YASKAWA SIEPC71061737B GA800 Drive Technical Reference
Possible Solutions
Possible Solutions
Possible Solutions
Possible Solutions